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Home , KX Andromedae, Shell star, Stellar mass

ISSN

Be NEWSLETTER

NUMBER

September

EditorinChief Technical Editor

Geraldine J Peters Douglas R Gies

email g jp etersmucenuscedu email giescharagsuedu

Space Sciences Center Center for High Angular Resolution Astronomy

University of Southern California Georgia State University

University Park University Plaza

Los Angeles CA Atlanta Georgia

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FAX FAX

Contents

Editorial

Working Group Matters

Working Group News Myron Smith

Jir Horn and Karel Juza P Harmanec

Contributions

New WUPPEAstro Observations of Hot K Bjorkman et al

Rapid Changes in the Sp ectrum of HD W Bidelman

Recent Activity in Cen O Stahl et al

Observation of a V R transition in Oph R Hanuschik et al

A simple and natural explanation for shell events R Hanuschik

Mo de Identication for doublewave Eri Stars L Balona

The Variation of Eri L Balona

Whats Happ ening

Forthcoming Multiwavelength Campaign on Eri G Peters

Intensive Campaign on Cas M Smith

IUE Campaign on Ori G Peters

More on h Persei J Fabregat

Polarization Activity in Omicron And D McDavid

Photometric Reduction Software P Harmanec

Newsletters on the WWW S Cranmer

NRP Movie on the WWW J Telting

Preprints Received

Bibliography

Meetings

The Be Star Newsletter is produced at and nancial ly supported by

the Georgia State University Department of Physics and Astronomy

The electronic version is available on

the World Wide Web httpcharagsueduBeNewsintrohtml

or by anonymous ftp ftp charagsuedu cd BeNews

Be Star Newsletter

EDITORIAL

We are happy to send you the th issue of the Be Star Newsletter We continue to

make the Newsletter available in three forms pap er plain ASCI I text that is sent

to email subscrib ers and also available via anonymous ftp and our version on the

World Wide Web WWW We continue to receive p ositive feedback on our electronic

Newsletter on the WWW and exp ect that it will continue evolve We are of course

eager to hear your suggestions for improvement and are esp ecially interested in your

opinions on whether we should continue to oer the email version in plain ASCI I

text or p erhaps switch to a pure LaTeX format

In Issue No we are pleased to publish the rst summary of the UV p olarimetric

observations on hot stars that were obtained with the Wisconsin Ultraviolet Photo

Polarimeter Exp eriment WUPPE on b oard the Astro Observatory payload own on

the space shuttle Columbia in March Also included in this large issue are rep orts

on recent activity in Cen Oph and HD Contributions discussing the

geometry of shell phases pulsation mo des in the Eri stars and further discussion

on the radial velocity variations in Eri itself are also a part of Issue No In our

section Whats Happ ening we include announcements of several campaigns on Be

stars and other newsworthy information of interest to the B star community The

usualPreprints Received Bibliography note the new style and information on

forthcoming Meetings are also a part of Issue No As usual we would like to

thank those who sent contributions and help ed compile the bibliography

We anticipate that Issue No will go to press around the rst of February In

order to insure that your contribution will app ear please send copies to the editor

inchief and technical editor by

January

We recommend that communications b e sent by electronic mail HYADESPETERS

g jp etersmucenuscedu giescharagsuedu and prefer that contributions and ab

stracts of submitted pap ers b e sent as LaTeX les Beginning with Issue No we

will require that abstracts b e submitted as LaTeX les and we will supply a template

for their preparation If it is not p ossible to transmit your contribution electroni

cally we request that it b e submitted in a cameraready condition see pap ers in the

current issue for style Contributions may also b e sent by FAX telephone number

but this is not recommended for pap ers that are longer than a half

page or those that contain gures due to the degradation of the resolution We pre

fer that illustrations b e sent by Email as a PostScript or encapsulated PostScript

le If this is not p ossible please send dark clear copies of the gures by regular

mail References should by typed in the newer simpler style recently adopted by the

Astrophysical Journal and other ma jor astronomical publications

I would like to wish you in advance a pro ductive fall and happy holiday season and

New I am lo oking forward to receiving your contributions in the months to

come

Gerrie Peters EditorinChief

Be Star Newsletter

WORKING GROUP MATTERS

Working Group News

Myron A Smith

Working Group Chairman

email BEIAUiuegtcgsfcnasagov

First Jo e Cassinelli and I would like to arrange a regional meeting of members of

the classical Be and BeXray communities next year for one day This would b e a

very informal gathering that would coincide with the American Astronomical So ci

ety meeting at the same time and place in Madison Wisconsin Jo e will set aside

appropriate space for a meeting but it will not b e a part of the AAS meeting p er

se We would b e delighted to welcome nonNorth American astronomers but they

should b e aware that they would have to register for attendance of the AAS meeting

separately The Wisconsin AAS meeting will take place b etween Sunday June and

Thursday June Our meeting would b e held on either Friday June or

Saturday June Should you b e interested please contact me Myron Smith

at beiauiuegtcgsfcnasagov

Second I want to remind you that the p ost of Scientic Editor of the Be Star Newslet

ter will b e op en at the end of the year as the current term expires The current editor

is of course Dr Gerrie Peters Gerrie has indicated that she would like to serve for

a new term and we should b e thankful that there will indeed b e an outstanding

candidate for the new term of At this time I would like to start to invite

other willing candidates as well Should anyone b e interested please contact me or

any of the other B Star Organizing Committee members

Third as you may b e aware at the last IAU General Assembly in August the

IAU approved a plan whereby the old Commissions would b e phased out in favor of a

new structure in which a web of working groups would grow and interconnect within

IAU Divisions This past winter the Division of Variable Stars and Close Binary

Stars to which we will want to b elong elected its Division chairman Dr Yoji Kondo

of the USA kondostarsgsfcnasagov Because this pro cess has just started

I have continued with my plan which will t in well with the new IAU structure

to request that our Working Group b e aliated with more than the original parent

Commissions on Stellar Sp ectra and Variable Stars Therefore I have requested an

aliation with the commissions on Theory of Stellar Atmospheres C and Close

Binary Stars C I am now awaiting a replies from Lawrence Cram and Marcello

Ro dono on this p etition

Pro ceeding to topical liaisons I have circulated an invitation for several Xray as

tronomers who study Xray Be binaries and High Mass Xray Binaries to join our

Working Group and several have asked to b e put on the distribution list of the Chair

and Newsletter Editors With the advent of ISO I am inviting interested members

of the OC and others to solicit interested researchers in the study of high mass IR

and radio emitting B stars to o

In early February several of us in the WG were fortunate enough to attend the

pulsation conference at Cap e Town South Africa As Mike Jerzykiewicz recently put

Be Star Newsletter

it the conference organizers in Cap e Town set new standards for hosting a conference

that will b e dicult for the rest of us to emulate but we should try In any

case the conference which concerned pulsators across the HRD was enjoyed by all

participants It seemed to me that the conference gave a little more emphasis and

certainly more results on RPNRP in B stars than other pulsation meetings over the

last For me one of the highlights was the talk by Pawel Moskalik on the

theory of pulsations in B stars based on the demonstration that the new OPALOP

opacities are sucient to drive radial and nonradial pulsations in B stars The new

results leave many questions unanswered but certainly are a breath of fresh air to

the observers who have had b een courageous enough in the past to interpret their

results There were several interesting p oster pap ers on B stars as well Everyone has

a favorite and mine was one by Telting et al on Cephei This pap er gives evidence

for rotational splitting of NRP mo des consistent with a rotational p erio d of several

days The evidence is apparently getting stronger for a magnetic dip ole as well as

secondary NRP mo des in this star

Jir Horn and Karel Juza

Two Czech stellar astronomers and rare men

Within less than a year the Stellar Department of the Astronomical Institute in

Ondrejov Czech Republic whose astronomers traditionally study hot stars and Be

stars in particular lost two of its most remarkable p ersonalities Drs Jir Horn and

Karel Juza Karel died on March just b efore he could defend his PhD

thesis devoted to a complex study of Dra Jirpassed away on December

at age Though very dierent in character they were b oth brilliant scientists yet

very mo dest p erhaps to o mo dest men For b oth of them their way to the profession

of astronomy was full of obstacles and b oth of them built homes for their families

with their own hands

Jir Horn was not allowed to study at the Charles University of Prague since his

parents were considered p olitical susp ects by the communists ruling the country

Fortunately enough Mirek Plavec now a professor at UCLA and at that time a

leader of the Ondrejov group of the Stellar Department accepted Jiras his research

assistant and later recommended him for the study at the University

Jir Horn had always b een full of energy and a source of ever p ertinent humour

sometimes tough but never injuring He was probably the cleverest of all of us but

he had no ambition to demonstrate his knowledge publicly He was very ecient in

work remarkably pro ductive but with little interest in publishing Actually I am

only aware of one single pap er which he himself published alone He was an excellent

team worker however and a notably skillful programmer as well Most of us still

use his ne userfriendly programs day and night since he had also developed the

control program for sp ectral observations with the coude sp ectrograph of the m

telescop e His energy was simply unbelievable He was helping his wife with their

three children to the extent that he seldom slept even after his duties at the telescop e

and his feeling of resp onsibility for all family members was extraordinary

He b ecame a Deputy of the Head of the Department and participated very actively

Be Star Newsletter

in the development of sp ectral observations with electronic detectors

Karel Juza b orn graduated from the Faculty of Mathematics and Physics

after defending a MSc thesis in astronomy However there were no professional

p ositions available for astronomers in Czechoslovakia at that time He therefore

accepted a p osition as night assistant at the SkalnatePleso Observatory and for many

years he travelled frequently b etween Prague where he himself built an apartment

as a member of a building co op erative and High Tatras in Slovakia a magnicent

mountain setting in which the Skalnate Pleso Observatory is lo cated He was also

there at the time of the Tschernobyl disaster when a spring rain splashed this area

with radioactive debris

Still at SkalnatePleso he started his p ostgraduate study which he continued later in

Ondrejov When he eventually joined the Ondrejov Stellar Department it was again

as a night assistant So on afterwards however he nally obtained a research p osition

there

Besides the preparation of his PhD thesis he did an enormous job of transferring a

huge archive of many thousands of UBV observations of Be stars secured at Hvar from

punched pap er cards into magnetic media and he participated in a new improved

reduction of these data on p ersonal computers

Very attentive always willing to help a man with a remarkable sense of dry humour

loving husband and father of two daughters he watched with a growing uneasiness

the coming split of Czechoslovakia His wife was b orn in Eastern Slovakia and the

time indeed came when they had to use an international train to visit her parents

Karel rushed to meet the deadline for nishing his thesis The promise of a more

quiet time in his life was so close when the insidious disease struck He fought for

two long months

Both Jirand Karel had acted as unifying elements for the whole department and all

of us shall miss them b oth for the rest of our lives

Petr Harmanec hecsunstelasucascz

Be Star Newsletter

CONTRIBUTIONS

New WUPPEAstro Observations of Hot Stars

Karen S Bjorkman the WUPPE Science Team

Space Astronomy Lab oratory

University of Wisconsin Madison

Abstract

During the day Astro mission ab oard the space shuttle Endeavour STS

in March new ultraviolet sp ectrop olarimetric observations of a number of

hot stars were obtained by the Wisconsin Ultraviolet PhotoPolarimeter Exp eriment

WUPPE Contemporaneous optical sp ectrop olarimetry was also obtained for many

of these ob jects from the Pine Blu Observatory PBO providing complete sp ec

trop olarimetric coverage from A to m Ob jects observed included OeBe

stars OB sup ergiants massive premainsequence stars luminous blue variables and

WolfRayet stars The new WUPPE observations have more than tripled the available

ultraviolet sp ectrop olarimetric data on these stars Combined with a large database

of prior optical observations from PBO and with the WUPPE data from the Astro

mission we now have an excellent sample of data with which to b egin detailed mo d

eling of the circumstellar environments of hot stars Since the new WUPPE data

are so recent they are still b eing carefully calibrated and reduced and so we cannot

yet draw rm conclusions from the data however we can present a summary of the

observations that were obtained

Instrumentation

WUPPE

The Wisconsin Ultraviolet PhotoPolarimeter Exp eriment WUPPE is a m tele

scop e and sp ectrop olarimeter It obtains simultaneous sp ectra and p olarization mea

surements from to A with a resolution of ab out A WUPPE is part of the

Astro Observatory space shuttle payload which consists of three ultraviolet telescop es

WUPPE the Hopkins Ultraviolet Telescope or HUT and the Ultraviolet Imaging

Telescope or UIT Observations with WUPPE were made during the day Astro

mission on the space shuttle Endeavour STS in March Previous observa

tions were made during the day Astro mission ab oard the space shuttle Columbia

STS in December In a number of cases the hot stars were also coobserved

with the IUE satellite to provide higher sp ectral resolution information

PBO

The University of Wisconsins Pine Blu Observatory PBO is a m telescop e

with a dedicated optical sp ectrop olarimeter attached It has b een in continuous

Be Star Newsletter

op eration for years obtaining optical supp ort observations for WUPPE and con

ducting optical p olarization survey programs Observing is carried out by a team of

undergraduate students along with UW faculty and sta Recent upgrades to the

PBO equipment include a CCD detector which has greatly improved the eciency

of the instrument and has extended the wavelength range from A out to m

allowing sp ectrop olarimetric observations to b e obtained across the Paschen jump

Observations

OeBe Stars

Our intent was to expand the sample obtained on Astro to include a range of

sp ectral types inclination angles and rotation velocities in order to have adequate

data for physical mo deling of the circumstellar disks see Figure for a graphical

representation of the coverage we actually obtained Data were obtained for

stars covering sp ectral types from O to B and v sin i values from to

kms Data are still in the pro cess of b eing calibrated so only a summary of the

observations can b e presented here

The OeBe stars observed with WUPPEAstro were the following sp ectral types

and v sin i values were taken from Slettebak

 Tau reobservation of Astro ob ject B IV esh v sin i

 Per B V esh v sin i binary

 Per B I I I esh v sin i binary

 Lib B IV esh v sin i

 Oph B V e v sin i

 Cyg B V e v sin i

 EW Lac B IV esh v sin i

 Tau B V esh v sin i

 FR CMa B V e v sin i

 Per B V e v sin i

 Per O e v sin i

 HD O V p v sin i

 Oph p ossible HAeBe star B IV e v sin i

 AE Aur HUT target O V e v sin i

OB Sup ergiants Luminous Blue Variables

The primary ob ject selected for observation in this class was the luminous blue vari

able LBV The observations were designed to search for UV and optical

p olarimetric variability on several timescales as a followup to results found from

Astro and from monitoring programs at PBO WUPPE obtained UV observa

tions of P Cyg during the Astro mission on March and In supp ort

Be Star Newsletter WUPPE/Astro-2 Coverage of Oe/Be Stars

400 HD 93521 φ Per 48 Lib

300 28 Tau EW Lac ψ Per ) s /

m 59 Cyg k (

i 200 ξ Per 51 Oph in ζ 48 Per s Tau FR CMa

v

χ Oph 100

AE Aur

0 O6 O8 B0 B2 B4 B6 B8 A0 Spectral Type

Figure 1. The range of spectral types and v sin i values for

Oe/Be stars observed with WUPPE on Astro-2.

PBO also obtained optical observations all within hours of the WUPPE obser

vations Quick lo ok data reduction shows that variability was detected in b oth the

optical and UV

Other ob jects in this class included AG Carinae which was observed as a followup

to HST sp ectrop olarimetry these data will require more careful calibration b efore

results can b e discussed and Cas and Cam which were observed as followups to

Astro results these stars are also used as interstellar prob es they are dominated

by interstellar p olarization but some intrinsic p olarization is present

Herbig AeBe HAeBe

In this class many ob jects were to o faint for WUPPE to observe However the

following four brighter stars were observed

 HD This star is b elieved to b e similar to HD which was observed

on Astro and showed evidence for bip olar ows It is thought to b e nearly

edgeon Quick lo ok data reduction do es not show evidence for the p olarimetric

p osition angle ip that would b e the signature of bip olar geometry however

further analysis is required Excellent supp orting data were also obtained with

IUE PBO and the University of Toledos Ritter Observatory

 AB Aur This star was observed as the test case for the near p oleon HAeBe

stars

Be Star Newsletter

 HD This star is thought to b e seen at midlatitudes Quick lo ok re

duction shows evidence for a p ossible p olarimetric p osition angle ip b etween

optical and UV which may indicate a bip olar geometry Accreting gas was

detected in the contemporaneous IUE observations Grady

 HD This is the central star of the reection NGC The

WUPPE observation consists of a sp ectrum only as the observation was to o

short to complete all the p olarimetric lter pairs

WolfRayet Stars

Observations of four WR stars of which had observations each were obtained as

part of a Guest Investigator GI program PI R SchulteLadbeck For details ab out

the observations see SchulteLadbeck The stars observed for this program

included

 HD EZ CMa or WR observed at dierent phases

 HD WR observations

 HD WR observations

 HD WR observation

In addition to the GI program several observations were made of HD a WR

star undergoing an apparent LBV outburst and some serendipitous observations were

made by osetting from HUT cluster targets Near the end of the mission WUPPE

was defo cused in order to observe Velorum a WR binary system which would

normally b e to o bright for WUPPE to observe b ecause of the unusual nature of the

observation the data will require careful calibration b efore results can b e interpreted

Serendipitous Observations

Adding to the planned WUPPE science programs for hot stars we also obtained data

on some early OB sup ergiants in clusters as serendipitous cop ointed observations

from a HUT GI program PI N Walborn WUPPE data on these HUT targets

will b e used as part of the WUPPE p olarization program on OB sup ergiants Also

numerous OB sup ergiants and OB stars observed as part of interstellar

medium program Anderson et al can b e used as comparisons for OeBe stars

The OeBe Stars Plans for Analysis

What the WUPPE PBO data can tell us ab out OeBe stars

Be Star Newsletter

With the new data obtained on Astro we now have an excellent cross section

of observations of OeBe stars across sp ectral types and v sin i values This will

allow us to test sp ecic mo dels such as the windcompressed disk WCD mo del

Bjorkman Cassinelli with a range of parameters We can compare mo del

eects on continuum p olarization with known eects of sp ectral line blanketing to

investigate the prop erties of the disk material We have already b egun to develop

mo dels using Monte Carlo metho ds to include multiple scattering eects Woo d

Bjorkman b which show that thin disk mo dels can repro duce the observed

levels of continuum p olarization For example ts to the PBO data on Tau show



that a disk with a half op ening angle is consistent with b oth the p olarization

wavelength dep endence and the m IR excess Woo d Bjorkman b In

addition the combination of WUPPE and PBO data provides go o d constraints on

mo del parameters across the entire UV and optical wavelength range For example

we can use Balmer Paschen continuum p olarization plus Balmer Paschen jumps

in p olarization to determine disk density and geometrical thickness and mo deling of

the Fe line blanketing of the UV p olarization will provide an estimate of the disk

temp erature

Quick lo ok reduction of the WUPPE data already shows that in cases of extreme

shell stars where sp ectral line blanketing due to the shell material is strong the

entire Balmer continuum p olarization is depressed strengthening the case for p ost

scattering attenuation due to the disk Woo d Bjorkman a This has implica

tions for what mo delling geometries can b e assumed for the disk material thickness

and extent of the disk These results conrm and expand the results from Astro

Bjorkman et al The new WUPPE data will also allow us to inves

tigate whether darkening eects can b e seen in the continuum p olarization

Bjorkman Bjorkman

The WUPPE and PBO data have b een obtained calibrated and reduced through

the eorts of many p eople We wish to thank all the members of the WUPPE and

PBO science teams We also thank the crew of STS and the NASA supp ort

team for a very successful and pro ductive Astro mission We thank Carol Grady

for obtaining the contemporaneous IUE data WUPPE has b een supp orted through

NASA contract NAS with the University of Wisconsin

References

Anderson CM et al BAAS

Bjorkman JE Cassinelli JP ApJ

Bjorkman JE Bjorkman KS ApJ

Bjorkman KS et al ApJ L

Bjorkman KS et al ApJ

Grady CA private communication

SchulteLadbeck RE BAAS

Slettebak A ApJ

Slettebak A ApJS

Woo d K Bjorkman JE ApJ

Woo d K Bjorkman JE BAAS

Be Star Newsletter

Rapid Changes in the Sp ectrum of HD

William P Bidelman

Warner Swasey Observatory

Case Western Reserve University

Cleveland OH



The mo deratelyhigh latitude star HD V b is classied as a

type A in the Henry Drap er Catalogue but as B by Balz Its sp ectrum app ears



in common with all other northern HD and somewhat fainter stars on ob jective

prism plates taken with CWRUs Burrell Schmidt now lo cated on Kitt Peak in fact

the ob ject is on two plates taken almost exactly four days apart on July and

Insp ection of these has revealed a very substantial change in the blueviolet

sp ectrum of the star

On the rst plate which is rather light the sp ectrum is that of a star of ab out

type B the H H and H lines are quite strong and mo derately sharp with H

b eing p erhaps somewhat weaker than normal But on the second plate there is clear

evidence of sharp emission in H shifted a bit longward of the line center and in H

and probably also in H This plate shows the higher members of the

as very broad and shallow

This sp eedy transformation from a nonBe to an emission ob ject is seldom seen

Reference to the Simbad database however indicates that HD has already

b een susp ected of having emission Abt has classied it as BVne No further

details are given and I know of no other sp ectroscopic observations Stromgren

photometry has b een discussed and published by Olsen

References

Abt H A ApJ

Balz A G A Publ Leander McCormick Obs pt I

Olsen E H AAS

Olsen E H AAS

Recent Activity in Cen

O Stahl A Kaufer B Wolf

CA Gummersbach Th Gang I Jankovics

H Mandel J Peitz Th Rivinius J Kovacs

Landessternwarte Heidelb erg Gothard Observatory Szombathely

The wellknown Be star Cen which had a strong H emission in the early s

Peters lost most of this emission in the s and showed only in o ccasional

outbursts weak H emission with pronounced VRvariations since then The sp ec

troscopic history of Cen until has b een summarized by Hanuschik et al

We have monitored Cen with Heros a b erlinked echelle sp ectrograph attached

to the ESO cm telescop e from Feb to Jun with a gap of two weeks in

April The sp ectrograph has two channels which are fed by a b eamsplitter With this

Be Star Newsletter

FIGURE Mean H prole obtained in FebJun

setup the wavelength ranges from A and A are covered in

one exp osure with a resolution of ab out One sp ectrum p er night was obtained

and only a few nights were lost due to bad weather In this short note we rep ort the

rst results ab out the H line of this monitoring

We found rather strong and symmetric doublep eak emission in H ab out as strong

as in the outburst rep orted by Peters with a maximum intensity of

 continuum level The emission prole shows clear nighttonight variations with a

timescale of ab out days but no qualitative variations in prole The mean prole

of the sp ectra is shown in Fig A time series of the individual sp ectra divided

by this mean sp ectrum is shown in Fig In Fig the equivalent width of H

as function of time integrated from to A is shown The variations in

equivalent width are more pronounced than in p eak intensity due to variable broad

wings of H These wings reach ab out  km sec

Since the emission had a similar strength already in Mar private communication

from Geraldine Peters it app ears that Cen is building up again its strong envelope

from the s Further observations of these secular changes could add to our

understanding of longterm changes in Be stars

References

Hanuschik RW Dachs J Baudzus M Thimm G Astron Astrophys

Peters GJ ApJ Suppl

Peters GJ ApJ L

Be Star Newsletter

FIGURE Timeseries sp ectrum of Cen around the H line The sp ectra have b een

divided by the mean sp ectrum shown in Fig In the b ox ab ove all quotient sp ectra are

plotted On the righthand side of this b ox the lo okup table is given Note the narrowing

of the broad emission wings during the rst half of the observing run

Be Star Newsletter

FIGURE Variations of the equivalent width of H from Feb to Jun Note that

the larger equivalent width at the end of the run compared to the b eginning is due to the

broad emission wings while the p eak intensity was similar

Observation of a V = R transition in Oph

RW HANUSCHIK S STEFL W HUMMEL M VRANCKEN

Astronomisches Institut RuhrUniversitat Postfach D

Bo chum Germany

Astronomical Institute Czech Acad of Sciences CZ Ondrejov

Czech Republic

Astrofysisch Instituut Vrije Universiteit Brussel Pleinlaan B

Brussel Belgium

As part of our longterm sp ectroscopic monitoring programme of Be stars at high

resolution we have rep eatedly observed the interesting equatorial Be star Oph

HR B IVVe v sin i km s We have mainly investigated the H and

the Fe i i emission line Our data shown here cover the ep o ch and

have b een measured at ESOs m CoudeAuxiliary Telescope observers Hanuschik

Hummel at the m telescop e at the GermanSpanish Observatory DSAZ on Calar

AltoSpain observers Hummel Vrancken and at the m Ondrejov telescop e ob

server Ste Resolution R has b een around except for the Ondrejov

data

1

Based on observations obtained at the Europ ean Southern Observatory La Silla Chile at the

GermanSpanish Observatory DSAZ Calar Alto Spain and at the Ondrejov Observatory Czech

Rep

Be Star Newsletter

FIGURE Comparison of the and H and Fe i i emission line proles of

Oph demonstrating the V R ! V R transition in November Fe i i lines are

shown on a ux scale expanded by a factor of Radial velocity scale is helio centric

In Oph showed a sudden onset of cyclic V R variability after at least

years of symmetric doublep eak structure V  R see Hanuschik et al AA

in press Its present full V R cycle time is only years rather short if compared to

other such Be stars which have typical cycle duration of ab out years With this

cycle time the rst V R transition must have o ccurred in early but escap ed

detection In we have b een fortunate enough to observe the second V R

transition see Fig

This transition o ccurred in November and app ears to have lasted only a few

months as a comparison of our data from September H R V November

R V and June V R clearly shows This duration is only a small

fraction of the full cycle time Such time b ehaviour agrees well with the exp ectation

that the slop e of the V R evolution is sinusoidal with much longer p erio ds of V R

asymmetry than with V R

An interesting observation is that shortly b efore the V R transition H and Fe i i

proles showed slightly opp osite V R b ehaviour in September R V in H

and V R in Fe i i This may b e partly due to the fact that in a certain critical

parameter range the V R ratios in the H and the Fe i i line may show opp osite

sign due to the sup erp osition of dierent line broadening mechanisms causing the

wineb ottletype inections and the prole p eaks Alternatively this may b e indica

tive of a certain time lag b etween the V R transition in b oth lines due to very

dierent optical depth and therefore dierent contributing disk regions

A very pronounced decrease in equivalent width o ccurred in November from

A to A in two months after the star had shown a stable value of A for

almost half a year b efore Almost months later W was again observed at higher

values A remaining constant thereafter for at least two months Such rather

strong disk variability seems to b e uncommon in this star If it is physically related

Be Star Newsletter

to the V R transition then this observation may b e interpreted as result of the

relatively small velocity gradient averaged across the whole emitting disk at the

moment of symmetry V R as compared to the situation shortly b efore and after

the transition when the velocity gradient b ecomes larger again

New not yet reduced sp ectra from Oct and March show a contin

uation of the trend of increasing V R ratio

We strongly encourage observers to continue to monitor this interesting Be star at

high sp ectral resolution in order to follow up its V R b ehaviour and to furthermore

do cument its emission strength variability pattern

A simple and natural explanation for shell events

RW Hanuschik

Astronomisches Institut RuhrUniversitat Bo chum Postfach

D Bo chum Germany

Circumstellar Be envelopes are cylindrical thin rotating structures ie disks For

Keplerian disks in fullydeveloped hydrostatic equilibrium the density law has the

wellknown form

) (

z

N r z N r  exp

h r

eg Pringle ARAA The scale height hr is given by hr r

c v r  r with the isothermal sound sp eed c and the Keplerian velocity at

s K  s

r r v r For values typical of Be stars M M R R and c

 K  s

km s we obtain hr  r

Such hydrostatic disks are concave in shap e for a p ower law dep endence of density

n

in the equatorial plane N r z N r r the exp onential slop e in vertical



direction pro duces density contours which have concave shap e for a certain range in

radius ie dZ dR / R see Fig There is a small critical inclination range

in which a chance exists that with increasing disk radius column depth in the disk

suddenly b ecomes large enough to pro duce a shell line

This o ccurs b ecause lines of sight then may intersect the disk twice the rst time very

close to the star the second time far away from the star In cases when the column

depth collected within the rst intersection is to o low to cause shell absorption Be

phase an increase of disk radius towards the second intersection area may pro duce

a shel l phase

Numerical calculations for shell line absorption in such disks Hanuschik in prepa

ration show that this sp ecic eect is to b e exp ected only around a certain critical

o o

value of inclination angle i   If the actual value of i is smaller an en

largement of r even by large factors is not capable to bring any appreciable amount

d

of absorbing material into the lines of sight At larger i shell absorption may o ccur

already in the region close to the star In Fig an example illustrates the shell

o

eect at i

Be Star Newsletter

FIGURE Sketch of the shell eect in a concave h / r disk Density contours for

the density law in Eq with n are shown for the cases N N Dotted

o o

lines indicate the range of shell absorption for i and i resp For the latter

case shell absorption b ecomes a sensitive function of outer disk radius R

d

FIGURE Calculated hydrogen shell line proles for a Keplerian velocity eld the

o

density law of Eq inclination angle and outer disk radii r broken line

d

thin solid line r thick solid line



Be Star Newsletter

This rather small inclination range satisfyingly explains why the shell transitions are

quite rare phenomena At larger inclination p ermanent shell absorption is to b e

exp ected provided a circumstellar disk exists at all and for i  i no absorption

phenomenon will o ccur

Though more rened mechanisms for shell events cannot b e excluded eg variable

scale height temp erature variation etc one should stress that this simple geometri

cal explanation works for isothermal disks with only one parameter allowed to vary

r

d

The doublewave Eri stars A problem with mo de

identication

LA Balona

South African Astronomical Observatory

PO Box Observatory Cap e Town South Africa

One of the puzzling characteristics of Eri stars is their ability to change from a

singlewave to a doublewave light curve and viceversa while the p erio d remains

unchanged The b est examples of this b ehaviour can b e found in Balona Sterken

Manfroid MNRAS for stars Ahmed and Ahmed in NGC

According to the NRP interpretation a changeover from singlewave to doublewave

implies a change of mo de in which the observed frequency is exactly doubled

If f is the observed frequency the frequency in a frame rotating with the star f is

given by

f f m

where m is the azimuthal wave number and is the frequency of rotation of the

star This means that if f is doubled so is f and m Alternatively one may satisfy

the frequencydoubling criterion yet maintain the same m value if the frequency in

the corotating frame is not doubled but instead takes on the value

0

f f m

This is no longer a straightforward resonance and there seems to b e no obvious

reason why this is to b e preferred

Gies IAU Symp osium Pulsation Rotation and Mass Loss in Earlytype

stars p nds that the NRP mo del gives m for nearly every star all those in

his Table I are singlewave as far as I can tell That means that when the changeover

to doublewave o ccurs the mo de changes to m If this mo de identication

p ertains to the ma jority of Eri stars it also p ertains to the two stars in NGC

mentioned ab ove But a basic calculation eg Dziembowski Acta Astr

shows that the light amplitude for a m mo de should only b e ab out

p ercent of the amplitude for a m mo de This is in conict with observations

doublewave light curves would have such a low amplitude as to b e scarcely observable

Yet it is estimated that ab out p ercent of Eri stars exhibit double waves Balona

MNRAS The double waves in the two stars in NGC mentioned

Be Star Newsletter

ab ove are certainly visible and have amplitudes which are within a factor of two of

the single wave This agrees more with the idea that in most singlewave Eri stars

the azimuthal spherical harmonic number is m and not m

I conclude that there is a problem in the mo de identication given by Gies Al

ternatively the mo de identication is correct in which case the straightforward

resonance no longer applies

The Radial Velocity Variation of Eri

LA Balona

South African Astronomical Observatory

PO Box Observatory Cap e Town South Africa

In a previous newsletter Gies Hahula Be Star Newsletter discuss a simula

tion of NRP and line prolevariability to mo del the Be star Eri They adopt the

o

following parameters R R i and v sin i km s which lead to a

e

rotation p erio d of d or d Of course the actual values are highly

uncertain b ecause it is very dicult to estimate the radius and angle of inclination for

any particular star The photometric and line prole variations give a p erio d of

hrs a frequency f d The frequency in the corotating frame is f

d for the sp ecied mo de m In other words this mo del gives a prograde wave

with a p erio d of P d for an observer rotating with the star

It is easy to show that the velocity p erturbation v is related to the eigenfunction

by

v i m

where is the observed angular frequency and is the angular frequency of rotation

Gies Hahula make the mistake of putting in the ab ove formula This leads

to a severe underestimate of the relative radius variation For the mo de m the

semiamplitude of the vertical velocity comp onent is given by

A ma N sin

r m

According to Gies Hahula the observed vertical velocity semiamplitude is

km s for which we obtain

a N sin  km

m

It follows that the fractional radial variation at the equator is Gies Hahula

obtain the dierence b eing due to the much smaller frequency of pulsation in

the corotating frame If we are to b elieve the ratio dT T dRR this leads to

a fractional temp erature variation dT T Not only is such a large temp er

ature variation unacceptable it would lead to a light variation of several tenths of a

and noticeable sp ectral changes during the pulsation it predicts a radial

velocity amplitude more than four times larger than predicted by Gies Hahula

Be Star Newsletter

All this is of course a purely academic exercise b ecause the real physical parameters

of Eri are unknown The values given ab ove derive from Smith Peters Grady

ApJ who estimate the error in the ratio to radius

squared of ab out The rotation p erio d has a large error which propagates to a

large error in the derived pulsation and temp erature amplitudes The only way of

tackling this problem is to use large numbers of stars Although the estimated radii

and pro jected rotational velocities for each star is p o orly determined their mean

prop erties b ecome quite well known sub ject of course to p ossible systematic errors

This is precisely what Balona MNRAS has done I show that the ratio

of the pulsation to rotational p erio ds is unity with a standard error of In the

example discussed ab ove this ratio is a dierence of standard deviations The

reason why Gies Hahula ignore this fact is not stated but it implies that the actual

relative temp erature amplitude is even larger than the already excessively high value

ab ove making nonsense of the NRP mo del

WHATS HAPPENING

Forthcoming Multiwavelength Campaign on Eridani

Gerrie Peters

Space Sciences Center USC

g jp etersmucenuscedu

The multiwavelength campaign on the bright Be star Eri announced

in the last issue of the Be Star Newsletter will b e carried through during the rst

two weeks of September IUE coverage will b egin with US on September at

UT and continue for eight contiguous shifts ending at UT on September

These observations will b e supp orted by highresolution optical sp ectroscopy at

Mt Stromlo Observatory from September and groundbased p olarimetry at

CTIO from September We anticipate observing Eri and DU Eri as secondary

targets We encourage other observers to join our eorts and are esp ecially in need of

optical photometry In addition to simultaneous observations we are also interested

in the pre and p ostcampaign b ehavior of the star

Intensive Campaign on Cas

Myron Smith

CSCIUE Observatory NASA Go ddard Space Flight Center Greenbelt

MD

I cant resist sharing with you the news of an award of of Hubble Space

TelescopeGHRS time on Cas to Richard Robinson and myself We have requested

the observations to fall in this satellites Continuous Viewing Zone meaning that

we hop e to get nearly hours of continuous integration at a cadence of ab out

second Recently I learned that my XTE prop osal was accepted as well so we will

Be Star Newsletter

b e getting simultaneous Xray observations along with new IUE sp ectra and some

optical observations as well What else we could use at this p oint would b e rapid

serial optical photometry Those dates are probably UT give or take

a day This will b e a once in a lifetime shot to lo ok into the connection b etween this

stars Xray and UVoptical activities

Announcement of an IUE Campaign on Orionis

Gerrie Peters

Space Sciences Center USC

g jp etersmucenuscedu

To investigate the origin of the Discrete Absorption Comp onents DACs in the wind

of the B I I Ie star Ori we have b een granted hours of IUE time during the

th and last episo de of the IUE Guest Observer program The plan is to observe

the star continuously for three days two rotation p erio ds at ep o chs of maximum

and loss Optical photometry from Villanova University since

has revealed that Ori undergo es outbursts quasip erio dically every months

The IUE observations have not yet b een ocially scheduled but the rst campaign

will probably o ccur in late December or early January Participants in this

pro ject include H F Henrichs D R Gies E F Guinan D McDavid and G J

Peters We invite members of the community to join our campaign We are esp ecially

in need of groundbased sp ectroscopic photometric and p olarimetric observations

from observing sites that have a go o d distribution in longitude Since the outbursts

in Ori are not strictly p erio dic we welcome frequent up dates on its emission state

We urge researchers who are involved in longterm monitoring programs of Be stars

to add this ob ject to their observing lists In addition to simultaneous observations

we are also interested in the pre and p ostcampaign b ehavior of the star If you

are interested in joining our eorts please contact any of the individuals mentioned

ab ove

More on Be Star h Persei

J Fabregat

Dept de AstronomaUniversidad de Valencia Burjassot

Valencia Spain

Shortly after the publication of the Newsletter I received a communication from

Dr Andreas Kaufer commenting on a highresolution H sp ectrum of star in h

Persei taken by him in September In this sp ectrum the H line is in almost pure

absorption A slight lling in is discernible when the observed prole is compared

with a mo deled one

The comparison of this sp ectrum with my Figure Be NL clearly shows

that star presents highly variable H emission characteristics The dates of the

two observations set an upp er limit of months to the development of the strong

emission line shown in Figure

Be Star Newsletter

Dr Kaufers work including the H prole has b een published in Astronomy and

Astrophysics AA

Polarization Activity in Omicron And

David McDavid

Limber Observatory Pip e Creek Texas

I have b een following the current emission episo de of o And with a new Glanprism

photop olarimeter on the m telescop e at Limber Observatory During the interval

in which the H emission b egan AugSept according to Petr Harmanec in

IAU Circular No there was no accompanying increase in p olarization The

p olarization remained low in V at least until early Jan which

was the last time I observed it This is conrmed by Ryuko Hiratas p olarimetry from

Do daira

When I resumed observing o And this year Jun the p olarization was unmistak

ably higher in V This is by far the highest p olarization I have ever

measured for o And going back to at McDonald Observatory and it has re

mained constant at this level through Jul Even without removing the interstellar

comp onent which is not well known but probably small the UBVRI data now show

the typical wavelength dep endence of the intrinsic p olarization of a Be star a p eak

in B a substantial drop in U and a steady decline through V R and I The earlier

wavelength dep endence was almost at It is hard to tell if there is any signicant

change in the p osition angle b ecause the earlier p olarization was so small that the

p osition angle was very uncertain

Petr Harmanec has compared Ondrejov H sp ectra from Nov and Jul

and comments The emission and shell is weaker now than in November but

in principle the sp ectrum shows little change b etween the two dates and remains

basically the same as we saw it during the whole Octob er Thus it seems that

the p olarization increase lagged the onset of H emission by several months although

b oth phenomena can b e considered to b e part of the same ongoing active phase A

p ossible interpretation is that if the emission and shell features are pro duced in the

outer region of the circumstellar envelope while the p olarization comes from the inner

region the delayed p olarization increase might indicate a gradual lling in of the

envelope More observations hop efully including sp ectrop olarimetry would certainly

help to clarify the picture

Be Star Newsletter

A Fortran Package for Reduction Transformation

to Standard Systems Archiving and Retrieval of Pho

to electric Observations

Petr Harmanec and Jiri Horn

Astronomical Institute Ondrejov Czech Republic

FAX and telephone Telex astro c

Internet hecsunstelasucascz

The authors make this package available to all interested colleagues up on the condi

tion that its usage will b e acknowledged in any publication based on data reduced

with it for instance by a reference to the pap er by Harmanec Horn and Juza

AAS

Here is how you can obtain the package

ftp sunstelasucascz or

login anonymous

password your email address

cd pubphot

get

A detailed instructions how to use the package can b e found in le MANUAL The

whole package is also available in compressed forms created by standard programs

LHA and PKZIP In that case you can only copy one le PHOTLZH or PHOTZIP

using the BINARY mo de of ftp

We strongly recommend you to notify us via email ab out your b ecoming a user of

this software Your email address will b e registered and you will b e notied ab out

any future improvement or extension of the software package

Information ab out upgrades for those who do not want to copy anew the whole

package

HEC Release March

Colour transformation co ecients H can all b e set zero if desired on input and

the program will calculate prop erly It was necessary to sp ecify small nonzero

values with the earlier version for numerical reasons

The builtin parameter PAS for the La Silla Observatory was set equal to and

the conversion program SILLAFOR was mo died prop erly to give correct

lo cal time on the output of HEC Everything was reduced correctly with the

earlier version only lo cal time printed was incorrect

1

Dr Jiri Horn died on December

Be Star Newsletter

Copy anew HECFOR SILLAFOR MANUAL

Manual release May

Dr S Ste developed conversion program ESOFOR which p ermits conversion

of output data from the ESO m telescop e at La Silla into input data of HEC

Copy anew MANUAL ESOFOR

Newsletters on the WWW

Steve Cranmer

Bartol Research Institute University of Delaware Newark DE e

mail cranmerbrivsbartoludeledu

Below is a listing of online newsletters from dierent elds of stellar astronomy

Be stars httpcharagsueduBeNewsintrohtml



Hot stars httpwwwinaoepmx eenenshothtml

AGB stars httpgagobservgrfrliensagbnewshtml

del Scu stars

linkDSSNDSSNHomepagehtml httpvenusastunivieacatsperl

The Be Star Newsletter certainly stands up in comparison although Im partial to

the header graphics myself ed note pro duced for us by Steve and colleagues

Also we at Bartol Stan Owocki Ken Gayley and myself are setting up a WWW

page on our own research Hot Star Astrophysics at Bartol which can b e accessed

at

homehtml httpwwwbartoludeledu cranmerhotstar

This page is currently under construction and really isnt ready for prime time yet

but I invite you to take a lo ok I also have some other astrophysicsrelated links and

details of my own work in my own home page

httpwwwbartoludeledu cranmercranmer homehtml

NRP Movie on the WWW

John Telting

Astronimcal Institute University of Amsterdam

email johnastrouvanl

I have pro duced an MPEG movie version of NRP and line prole variability for our

annual science exibition here in Amsterdam You can nd them on the World Wide

Web as httpwwwastrouvanlanimjoopmpg

and

httpwwwastrouvanlanimjoepmpg

Be Star Newsletter

PREPRINTS RECEIVED

Be phenomenon extending to lower in the Magel lanic Clouds

CA Gummersbach FJ Zickgraf and B Wolf

AA in press

email cgummershplswuniheidelbergde

URL httpwwwlswuniheidelbergdecgummers

An analysis of the four recently discovered Be stars Hen S S S and S

in the Large Magellanic Cloud has b een carried out using lowresolution IUE sp ectra

ESO m CASPEC sp ectra and ESO m and m UBV and JHK photometry

resp ectively LTE mo del atmospheres have b een tted to the observed continuum

energy distributions in order to derive the stellar parameters The results are T

e

K R R and log LL for Hen S T K R R

e

and log LL for Hen S and T K R R and log LL

e

for Hen S

The presence of absorption lines in the optical sp ectrum of the Be Ib star Hen S

allowed an additional LTE line analysis for this star using Balmer He i Si i i Mg i i

and Fe i i lines to derive T K R R log LL log g

e

M km s v sin i km s and M



Our investigation shows that the class of Be stars in the Magellanic Clouds extends

to luminosities of ab out log LL ie much lower than those of the previously

studied Be sup ergiants This result reinforces the imp ortance of axial symmetry in

large regions of the HertzsprungRussell diagram

Orbital elements of multiple spectroscopic stars

P Hadrava

AAS in press

A metho d for simultaneous decomp osition of sp ectra of binary and multiple stars us

ing FFT and the solution of orbital elements by SIMPLEXoptimization is describ ed

The LaTeX preprint is accessible in les KORELTEX and KORELPCX by FTP at

directory ftppubfotel at server SUNSTELASUCASCZ

Shel l lines in disks around Be stars I Simple approximations for Keplerian disks

RW Hanuschik

AA in press accepted July

email rwhwsaastroruhrunib o chumde

This pap er investigates shell absorption lines o ccurring in Be star disks seen edgeon

These lines are counterparts of absorption troughs in P Cygtype proles for dierent

Be Star Newsletter

geometry and kinematics and oer a prob e of a small p ortion of the circumstellar

disk This investigation concentrates on Fe lines as prototype examples for metallic

shell lines which have an extremely small thermal width km s at K

As a simple though not unphysical mo del a purely Keplerian isothermal disk in

hydrodynamic equilibrium is adopted The intention of this pap er is to provide simple

approximations for easy use It is shown that resulting Fe shell proles consist of a

broad kinematic part and a narrow thermal core the narrowness of which dep ends

on the intrinsic Doppler width of the line The outer disk radius r may cause

d

under certain circumstances cusps at radial velocities V r These cusps can

d

d

b ecome the deep est p oints in the line prole thus causing a central p eak Finally it

is demonstrated that if the disk b ecomes turbulent the central p eak disapp ears and

the Fe shell proles are identical to hydrogenic lines from nonturbulent disks

V R variability and global oscil lations in Be star disks

RW Hanuschik W Hummel O Dietle and E Sutorius

AA in press accepted January

email rwhwsaastroruhrunib o chumde

We present highresolution H and Fe II sp ectroscopic data on the emission line

b ehaviour of ve selected Be stars HR Cen Lib Ara Oph four of

them showing cyclic V R line prole variability in the p erio d With the

exception of the Lib these stars temp orarily also show a characteristic

asymmetric steepletype prole shap e in their Fe II emission line which we

have chosen as characteristical optically thin emission line These proles are very

similar in all three stars In contrast the star Ara exhibits symmetric doublep eak

proles over the whole investigated p erio d

Steepletype proles are cyclically variable in the sense that they show asymmetric

line proles for almost half a cycle then asymmetry inversion in the second halfcycle

and reapp ear with the same shap e after a full cycle which lasts ab out years

We demonstrate that this characteristic steepletype prole shap e and the longterm

V R variability pattern known since long are two manifestations of the same physical

phenomenon We provide arguments in favour of the global disk oscillation scenario

as causing a largescale p erturbation of the quasiKeplerian circumstellar disk which

precesses under the inuence of the nonspherical gravitational p otential of the central

star

Nonaxisymmetric Be star circumstellar disks

W Hummel and M Vrancken

Astrofysisch Instituut Vrije Universiteit Brussel

Pleinlaan B Brussel Belgium

A new high resolution and high signaltonoise ratio sp ectroscopic study of H Fe i i

and He i emission lines of northern and equatorial Be stars is presented

Be Star Newsletter

The line proles are analyzed in order to test predictions of the recently prop osed

mo del of global disk oscillations The Fe i i and He i line proles are used to derive

the kinematics and the radial extension of the circumstellar disklike plasma Based

on line prole derivatives we present a new metho d the separation of the inection

p oints SIP to resolve the convolved p eaks of H wineb ottletype proles The

newly derived p eak p ositions are used to determine H emission disk radii and mean

optical line depths along the line of sight We nd that these improved H disk radii

are smaller and closer to Fe i i disk radii than those H disk radii derived from pure

p eak separations We nd evidence that class proles originate from quasiKeplerian

disks with a nonaxisymmetric density distribution

Hydrodynamical Simulations of Corotating Interaction Regions and Discrete Absorp

tion Components in Rotating OStar Winds

Steven R Cranmer and Stanley P Owocki

submitted to ApJ

email cranmerbartoludeledu

We present twodimensional hydrodynamical simulations of corotating stream struc

ture in the wind from a rotating O star together with resulting synthetic line proles

showing discrete absorption comp onents DACs An azimuthal variation is induced

by a lo cal increase or decrease in the radiative driving force as would arise from a

bright or dark star sp ot in the equatorial plane Since much of the emergent wind

structure seems indep endent of the exact metho d of p erturbation we exp ect similar

morphology in winds p erturb ed by lo calized magnetic elds or nonradial pulsations

as well as by either rotationallymo dulated structure or transient mass ejection

We nd that bright sp ots with enhanced driving generate highdensity lowspeed

streams while dark sp ots generate lowdnesity high sp eed streams Corotating in

teraction regions CIRs form where fast material collides with slow material eg

at the leading trailing edge of a stream from a dark bright sp ot often steep ening

into sho cks The unp erturb ed sup ersonic wind obliquely impacts the highdensity

CIR and sends back a nonlinear signal which takes the form of a sharp propagating

discontinuity kink or plateau in the radial velocity gradient These features

travel inward in the comoving frame at the radiativeacoustic characteristic sp eed

and thus slowly outward in the stars frame We nd that these slow kinks rather

than the CIRs themselves are more likely to result in highopacity DACs in the ab

sorption troughs of unsaturated P Cygni lines Because the hydrodynamic structure

settles to a steady state in a frame corotating with the star the more tightlyspiraled

kinks sweep by an observer on a longer time scale than material moving with the wind

itself This is in general accord with observations showing slow apparent accelerations

for DACs

Be Star Newsletter

The EarlyType Variables

LA Balona

Submitted to ApSS

We review the observational status of several dierent kinds of intrinsic variables

among the earlytype stars and attempt to interpret the variations in terms of our

current understanding of stellar pulsation Four distinct types of intrinsic variable

can b e dened the Cep Per Oph and Eri stars A simple observational

classication scheme which is readily interpreted in terms of pulsation prop erties is

prop osed The limits of the and pulsation constants for the Cep

and Per stars are discussed Problems with the interpretation of Eri stars in

terms of pulsation are p ointed out The observations are consistent with rotational

mo dulation A problem with mo de identication in Eri stars is discussed

Tests of the pulsation and models for the periodic Be stars

LA Balona

MNRAS in press

We review the correlation b etween the pro jected rotational velocity and the p erio ds

of the p erio dic Be stars Eri variables By estimating radius from the sp ectral

type and assuming that the photometric p erio d is the same as the p erio d of rota

tion the equatorial rotational velocity can b e derived We discuss and revise the

sp ectral typeradius calibration The resulting distribution of equatorial velocities

is not signicantly dierent from that of a statistical deconvolution of a large num

b er of Be stars assuming random orientation of the axes of rotation We conclude

that the photometric p erio d is the same as the rotation p erio d within p ercent It

follows that the pulsation and starsp ot mo dels for these stars are practically indistin

guishable b ecause the pulsational velocity is restricted to very low values We then

derive an expression for the radial velocity to light amplitude ratio The observed

ratios are much higher than predicted from the pulsationstarsp ot mo del There are

several other reasons why the pulsationstarsp ot mo del needs to b e abandoned A

velocity eld of unknown origin of several tens of km s is required to explain the

observations

EUVE Spectroscopy of Canis Majoris B IIIII from to A

JP Cassinelli DH Cohen JJ MacFarlane JE Drew AE LynasGray

I Hub eny JV Vallerga BY Welsh and MG Hoare

submitted to ApJ

Observations of the bright CMa B I II I I made with the Extreme

Ultraviolet Explorer EUVE are presented We rep ort on the continuous energy

distribution photospheric line identication and the variability of the star as well as

Be Star Newsletter

the physical implications for the structure of the lo cal interstellar medium The star

is one of the strongest EUV sources in the long wavelength sp ectrometer of EUVE

and one of only two earlytype stars whose photospheric continuum was detected

by the EUVE sp ectrometers This pap er is primarily concerned with the p ortion of

the sp ectrum that lies b etween the neutral helium ionization edge at A and an

eective cuto by interstellar absorption near A As in our EUV analysis of the

B II star CMa we found that lineblanketed mo del atmospheres are not capable

of predicting an energy distribution which matches observations in all wavelength

regions Consequently we derived two set of basic parameters for the star T

e

K log g and T K log g dep ending whether we accept

e

the measured angular diameter or require an exact agreement b etween mo dels and

the observed visual ux For the higher T mo del the predicted EUV ux is in

e

agreement with observations while for the lower T the stars EUV continuum is

e

ab out times brighter than the predictions In either case the star do es not show

the order of magnitude EUV excess that was seen in CMa The EUVE data also

provide information concerning the low density interstellar medium in the direction

of CMa We derive a neutral hydrogen column density of   cm and

estimate a lower limit for the neutral helium column density of  cm The

EUVE sp ectrum shows many strong photospheric absorption features similar to that

of CMa Evidence for a is seen in the O V A absorption feature

There is sp ecial interest in CMa b ecause it is among the brightest of the Cephei

class of variables The pulsations in this class of star manifest themselves primarily

as p erio dic eective temp erature changes We nd that the semiamplitude of the

change is K for the primary p erio d This result is consistent with that derived

from an analysis of the UV continuum by Beeckmans Burger but our error

bars are signicantly smaller The general agreement implies that the pulsations do

propagate b etween the layers where the optical and UV continua are formed and

the layers where the EUV continuum forms which is ab out six density scale heights

higher in static mo dels The p ossibility that some pulsational energy dep osition could

o ccur within the outer is discussed Our observations taken over two

time intervals separated by days resulted in the detection of the b eat phenomenon

owing to the three oscillation p erio ds of CMa

Be Star Newsletter

BIBLIOGRAPHY

compiled by D R Gies A M Hub ert J Jugaku G J Peters

Constraints on Be Star Geometry Derived from Combined Photometric IR Excess

and Optical Polarimetry Data

AERTS C MOLENBERGHS G AA

The Spin Period and Relation for BeStar Binary Sys

tems

APPARAO K M V AA

HighResolution Sp ectroscopy of Southern and Equatorial Be Stars Flux Excess at

A

BALLEREAU D CHAUVILLE D ZOREC J AAS

Some Fe I I EmissionLine Proles of Nine Southern Be Stars

BALLEREAU D CHAUVILLE J ZOREC J AAS

ROSAT XRay Light Curves of EarlyType Stars

BERGHOEFER T W SCHMITT J H M M ApSS

Are Late BType Stars Intrinsic Xray Emitters

BERGHOFER T W SCHMITT J H M M AA L

Ultraviolet and Optical Sp ectroscopy of a B Sup ergiant Star in M

BIANCHI L LAMERS H J G L M HUTCHINGS J B MASSEY P KU

DRITZKI R HERRERO A LENNON D J AA

Stellar Wind and Kepler Disk Interactions in Hot Stars abstract

BJORKMAN J WOOD K BAAS

Sp ectrop olarimetric Variability in OB Stars

BJORKMAN K S ApSS

The Eects of Gravity Darkening on the Ultraviolet Continuum Polarization Pro

duced by Circumstellar Disks

BJORKMAN J E BJORKMAN K S ApJ

Winds of magnetic B stars

BOLTON C T ApSS

ROSAT and EUVE Observations of B Stars

CASSINELLI J P ApSS

EUVE Sp ectroscopy of Canis Ma joris B I I from to A

CASSINELLI J P COHEN D H MACFARLANE J J DREW J E LYNAS

GRAY A E HOARE M G VALLERGA J V WELSH B Y VEDDER P

W HUBENY I ApJ

XRay Emission in Wind Instability Simulations

COOPER R G OWOCKI S P ApSS

The Eect of Oblateness and Gravity Darkening on the Radiation Driving in Winds

from Rapidly Rotating B Stars

CRANMER S R OWOCKI S P ApJ

Be Star Newsletter

The Subarcsecond Micron Size of LkH Constraints on Circumstellar Dust

DANEN R M GWINN C R BLOEMHOF E E ApJ

The Massive Winds of Luminous Peculiar BType Stars

DE ARAUJO F X AAS

The Equatorial Plane of Be Stars an Outow Driven by Optically Thin Lines

DE ARAUJO FX AA

Origin and Evolution of SemiDetached Binaries Lyrae and SV Centauri

DE GREVE J P LINNELL A P AA

On the Further Observations of the BeShell Star V Aql

DENIZMAN L KOKTAY T SAYGAC T KOCER D ApSS

The Eclipse of Cygni

EATON J A BELL C AJ

S Mus B Revisited

EVANS N R MASSA D TEAYS T J AJ

The Binary System of the Be Star KX Andromedae

FLOQUET M HUBERT A M HUBERT H BALLEREAU D CHAUVILLE

J AA

The Theoretical Polarization of Pure Scattering Axisymmetric Circumstellar En

velopes

FOX G K ApJ

A Study of Carina OB Asso ciation Analysis and Discussion of the Data

GARCIA B ApJ

The OB Asso ciation LH in the Large Magellanic Cloud

GARMANY C D MASSEY P PARKER J W AJ

AG Persei Absolute Dimensions and Membership of Perseus OB

GIMENEZ A CLAUSEN J V AA



XRay Observations of the Peculiar Be Star LSI

GOLDONI P MEREGHETTI S AA

XRay Emission from the PSR B System Near Apastron

GREINER J TAVANI M BELLONI T ApJ L

A New VR Cyclic Change of H in Tau

GUO Y IBVS No

A Detection of Moving Bumps in the Emission Proles of the Be Star FX Lib

GUO Y IBVS No

Cassiop eiae Evidence for a Be StarWhite Dwarf XRay Binary

HABERL F AA

Shell Lines in Disks around Be Stars I Simple Approximations for Keplerian Disks

HANUSCHIK RW AA

VR Variability and Global Oscillations in Be Star Disks

Be Star Newsletter

HANUSCHIK R W HUMMEL W DIETLE O SUTORIUS E AA

Interpretation of the LongTerm Variation in LateType Active Be Stars

HIRATA R PASJ

Stromgrenand H Photometry of OB Stars in Serp ens

KALTCHEVA N KUNTCHEV P ApSS

Growth of the LineProle Variation Region During Be Episo des in Eridani

KAMBE E ApSS

The Galactic Distribution of Chemical Elements as Derived from BStars in Op en

Clusters NGC S and S

KILIANMONTENBRUCK J GEHREN T NISSEN P E AA

XRay Emission of the Be Star Binary PSR

KING A COMINSKY L ApJ

Radial Velocity Studies of AType Shell Stars

LEVATO H MALARODA S JASCHEK C JASCHEK M AA

XRayInduced Ionization in the Winds of EarlyB Stars Constraints Imp osed by

EUVE abstract

MACFARLANE J J COHEN DH CASSINELLI J P BAAS

XRay Induced Ionization in the Winds of NearMainSequence O and B Stars

MACFARLANE J J COHEN D H WANG P ApJ

XRay Binary Pulse vs and the HighEnergy Continuum

MAISACK M AdSpR No

H Emission and Absorption From a Lo calized Region Ab ove the Surface of a Be

Star

MARLBOROUGH J M ApJ

Wind Variability in Intermediate B Sup ergiants

MASSA D FULLERTON A PRINJA R ApSS

Variable Polarization in the Be Star Eridani abstract

McDAVID D FRUEH M BAAS

Serendipitous EUV Sources Detected During the First Year of the Extreme Ultraviolet

Explorer Right Angle Program

MCDONALD K CRAIG N SIRK M M DRAKE J J FURSCIONE A

VALLERGA J V MALINA R F AJ

Stellar Wind and Stellar Disc Mo dels of Disp ersion and Rotation Measure Variations

in the PSR BSS Binary System

MELATOS A JOHNSTON S MELROSE D B MNRAS

LongTerm Photometry of Be Stars I Fading Events and Variations on Time Scales

of Years

MENNICKENT R E VOGT N STERKEN C AAS

Be Star Newsletter

Instability and Variability of HotStar Winds An International Workshop Isleaux

Coudres Queb ec Province Canada Aug

MOFFAT A F J OWOCKI S P FULLERTON A W STLOUIS N

ApSS

Studies of Binary Stars in the Magellanic Clouds Sp ectroscopic Orbits of Four

Massive Eclipsing Binaries

NIEMELA V S BASSINO L P ApJ

Multiwavelength Observations of the Be StarXRay Binary EXO during

Outburst

NORTON A J CHAKRABARTY D COE MJ EVERALL C FINGER M

H PRINCE T A ROCHE P STOLLBERG MT WILSON R B

MNRAS

The Formation of Be Stars in Close Binary Systems The Imp ortance of Kicks and

Angular Momentum Loss

PORTEGIES ZWART S F AA

Decoupled Line Driven Outow around B and Be Stars

PORTER J M DREW J E AA

EmissionLine PreMainSequence Stars and XRay Sources in Orion

PRAVDO S H ANGELINI L ApJ

A Comparison of BStar Sp ectral Types on the MK and Ultraviolet Classication

Systems abstract

ROUNTREE J SONNEBORN G BAAS

The Infrared and Radio Continuum of OBStars

RUNACRES M BLOMME R ApSS

Sp ectrop olarimetry of Hot Luminous Stars

SCHULTELADBECK R E ApSS

The Infrared Fluxes of Early Type Stars

SHYLAJA B S BASI

Dynamic pro cesses in Be star atmospheres I I I Rapid Multiwavelength Variability

in Cassiop eiae

SMITH M A ApJ

An of Ultraviolet P Cygni Proles

SNOW T P LAMERS H J G L M LINDHOLM D M ODELL A P

ApJS

Line Proles and Intensity Maps from an AxiSymmetric Radiative Wind Mo del for

Be Stars

STEE P DE ARAUJO F X AA

Cassiop eiae Revisited by Sp ectrally Resolved Interferometry

STEE P DE ARAUJO F X VAKILI F MOURARD D ARNOLD L BON

NEAU D MORAND F TALLONBOSC I AA

Simultaneous Photometric and Sp ectroscopic Monitoring of Rapid Variations of the

Be Star Newsletter

Be Star Centauri

STEFL S BAADE D HARMANEC P BALONA L A AA

Evidence for Ellipsoidal Variations of the Be Star Binary HD

STERKEN C VOGT N MENNICKENT R AA

Tomographic Separation of Comp osite Sp ectra I I I UV Detection of the Hot Com

panion of

THALLER M L BAGNUOLO W G Jr GIES D R PENNY L R

ApJ

Continuum Energy Distribution of Be Stars in the Optical Region

TUR N S GORAYA P S SHARMA SD PASP

H Emission and Infrared Excess in Be Stars Probing the Circumstellar Disc

VAN KERKWIJK M H WATERS LBFM MARLBOROUGH J M

AA

Circumstellar Gas and Dust in Ophiuchi AIVe RN

WATERS LBFM VAN DEN ANCKER M E BAAS F VAN DER BLIEK

N S BONTEKOE T R GEBALLE T R GRADY C A KESTER DJM

OUDMAIJER R D SANDELL G THE P S R VAN WINCKEL

H AA

The HI Infrared Line Sp ectrum for Be Stars with LowDensity Discs

ZAAL P A WATERS LBFM MARLBOROUGH J M AA

MEETINGS

 November

Colliding Winds in Binary Stars Celebrating Dr Jorge Sahades th

birthday La Plata Argentina Contact Virpi Niemela Observatorio Astro

nomico de La Plata La Plata Argentina

Email windsfcaglpfcaglpunlpeduar

 or June

WG sp onsored informal meeting following the AAS meeting in Madison Wis

consin see Section of this issue

 June

A Half Century of Stellar Pulsation Interpretations A Tribute to

Arthur N Cox Los Alamos NM Contact Joyce A Guzik Los Alamos

National Lab oratory

Email joylanlgov

Be Star Newsletter