COMMISSIONS 27 AND 42 OF THE I.A.U. INFORMATION BULLETIN ON VARIABLE

Nos. 4001 - 4100 1994 March - 1994 October

EDITORS: L. Szabados and K. Olah KONKOLY OBSERVATORY H-1525 BUDAPEST P.O. Box 67, HUNGARY

HU ISSN 0374 - 0676 CONTENTS

4001 DISCOVERY OF SHORT TIME-SCALE OSCILLATIONS IN HD74292 A.V. Kusakin 1 March 1994

4002 MAGNITUDE SEQUENCES IN THE FIELDS SURROUNDING UX ANTLIAE AND UW CENTAURI L.A. Milone 9 March 1994

4003 II-52 - A NEW SHORT PERIOD VARIABLE IN M3 Yao Bao-an, Zhang Chun-Sheng, Quin Dao 16 March 1994

4004 V477 Cas = NSV 269 Jan Manek 18 March 1994

4005 UBV PHOTOELECTRIC AND PHOTOGRAPHIC PHOTOMETRY OF CASSIOPEIAE 1993 U. Munari, T.V. Tomov, A. Antonov, R. Passuello, G. Sostero, A. Lepardo, I. Dalmeri 21 March 1994

4006 IMPROVED POSITIONS OF SOUTHERN NSV STARS. III. C.E. Lopez, H. Mira 21 March 1994

4007 PHOTOELECTRIC INTERMEDIATE BAND PHOTOMETRY OF SN 1993J R. Pressberger, H.M. Maitzen 22 March 1994

4008 A PHOTOMETRIC STUDY OF THE NEW ECLIPSING BINARY HD2155 J. Watson, C. Lloyd 24 March 1994

4009 TIMES OF MINIMA OF NINE ECLIPSING BINARIES C.H.S Lacy, G.W. Fox 24 March 1994

4010 NEW PHOTOMETRIC VARIABLE STARS IN THE FIELD OF SOUTHERN OPEN CLUSTERS A.E. Piatti, J.J. Claria 5 April 1994

4011 DIFFERENTIAL BV PHOTOMETRY OF THE EW VARIABLE NSV7457 Her R. Diethelm 7 April 1994

4012 PHOTOMETRY OF KR AURIGAE 1985-1988 V. Popov, Z. Kraicheva, A. Antov 7 April 1994

4013 DISCOVERY OF 6.2-MINUTE OSCILLATION IN THE Ap Sr STAR HD 86181 D.W. Kurtz, P. Martinez 15 April 1994 4014 TRANSIENT PERIOD FOUND IN THE BY Dra VARIABLE OU GEMINORUM D.E. McKenzie, R.B. Herr 18 April 1994

4015 EP And = NSV 598 J. Manek 21 April 1994

4016 EK Lac = NSV 14025 J. Manek 21 April 1994

4017 IX And = NSV 372 J. Manek 22 April 1994

4018 TIMES OF MINIMUM OF ECLIPSING BINARIES IN AND NEAR CENTAURUS G.W. Wolf, P.W. Ratzlaff 26 April 1994

4019 OBSERVATIONS OF A SYMBIOTIC NOVA IN SAGITTARIUS E.K. Grebel, H.W. Duerbeck, J. Greiner, G.A. Richter 5 May 1994

4020 POSITIONS OF VARIABLE STARS IN PLAUT'S FIELD 1 S.V. Antipin, N.N. Kireeva, N.N. Samus 5 May 1994

4021 POSITIONS OF VARIABLE STARS IN PLAUT'S FIELD 2 S.V. Antipin, N.N. Kireeva, N.N. Samus 5 May 1994

4022 FURTHER CONFIRMATION THAT THE Be STAR 27CMa IS A Beta Cep VARIABLE L.A. Balona, K. Krisciunas 10 May 1994

4023 THE OBSERVATIONS OF SUPERHUMPS IN T LEONIS Ch. Kunjaya, T. Kato, R. Hirata 11 May 1994

4024 THE VARIABILITY OF HD 162211 = 87 HERCULIS BETWEEN 1984 AND 1993 B.A. Skiff, G.W. Lockwood 11 May 1994

4025 UBV PHOTOMETRY OF CH CYGNI IN 1993: INCREASING ACTIVITY K.P. Panov, J.S.W. Stegert 16 May 1994

4026 FG Sge: RISE FROM MINIMUM V. Simon 16 May 1994

4027 TIMES OF MINIMA FOR SOME ECLIPSING BINARIES Z. Muyesseroglu, S.O. Selam 19 May 1994

4028 FURTHER PHOTOMETRY OF alpha Ori AND gamma Ori K. Krisciunas 19 May 1994 4029 IQ Cyg = V 1290 Cyg J. Manek 20 May 1994

4030 POSITIONS FOR STARS IN THE FIELDS OF UX ANTLIAE AND UW CENTAURI B.A. Skiff 20 May 1994

4031 V 1177 Cyg = NSV 12848 J. Manek 24 May 1994

4032 THE VARIABILITY OF W 134 R.H. Koch, P.M. Perry, G.C. Kilambi 26 May 1994

4033 IO DELPHINI - CLOSELY RELATED TO WZ SAGITTAE? G.A. Richter, H.J. Brauer 27 May 1994

4034 NEAR INFRARED PHOTOMETRY FOR THE Be STAR MX Per Xiao-zhen Guo, Jun-jie Wang 30 May 1994

4035 RAPID SPECTRAL VARIATIONS OF THE Be STAR gamma Cas Xiao-zhen Guo, Jun-jie Wang, Shi-yang Jiang 30 May 1994

4036 UBV OF RT And FOR 1992 A. Dapergolas, E. Kontizas, M. Kontizas 31 May 1994

4037 IMPROVED FOR VARIABLE STARS M. Morel 31 May 1994

4038 CALL FOR OBSERVATIONS OF BH CAS T.S. Metcalfe 1 June 1994

4039 TIMES OF LIGHT MAXIMUM OF VZ CANCRI: 1994 SEASON A. Arellano Ferro, J.J. Avila, F. Gonzalez 6 June 1994

4040 NON-CEPHEID CHARACTER OF V588 Cas D.L. DuPuy, R.H. Bloomer 16 June 1994

4041 PHOTOELECTRIC PHOTOMETRY OF VW CEPHEI IN 1993 B.P. Abbott, D.J. Rumignani 22 June 1994

4042 ON THE STABILITY OF SPOTTED REGIONS ON STELLAR SURFACES OF WEAK-LINE T TAURI STARS K.N. Grankin 30 June 1994

4043 OUTBURST OBSERVATIONS OF LL ANDROMEDAE S.B. Howell, G.M. Hurst 30 June 1994 4044 VARIATIONS OF THE Ap STARS IN NGC2169 J. Manfroid, P. Renson 1 July 1994

4045 NEW EPHEMERIS OF THE BINARY SYSTEM 44i BOOTIS O. Gherega, L. Farkas, A. Horvath 4 July 1994

4046 NEW FLARE STARS IN THE CYGNUS T1 ASSOCIATION REGION E.S. Parsamian, E. Chavira, G. Gonzalez 7 July 1994

4047 NEW FLARE STARS IN THE REGION OF OPHIUCUS AND SCORPIUS E.S. Parsamian, E. Chavira, G. Gonzalez 7 July 1994

4048 OPTICAL SPECTROSCOPY OF A FLARE ON PROXIMA CENTAURI B.M. Patten 12 July 1994

4049 OPTICAL SPECTROSCOPY AND PHOTOMETRY of EX Lupi B.M. Patten 12 July 1994

4050 V800 Aql IS A CLASSICAL CEPHEID S.V. Antipin, S.Yu. Shugarov 12 July 1994

4051 1992, 1993 BV PHOTOELECTRIC OBSERVATIONS OF CG Cyg A. Dapergolas, E. Kontizas, M. Kontizas 15 July 1994

4052 THE PERIOD OF AG PHOENICIS HAS DECREASED M.A. Cerruti 25 July 1994

4053 PHOTOMETRY FOR STARS IN THE FIELD OF V BOOTIS B.A. Skiff 27 July 1994

4054 PHOTOMETRY OF STARS IN THE FIELD OF S PERSEI B.A. Skiff 28 July 1994

4055 PHOTOMETRY OF STARS IN THE FIELD OF ZZ DRACONIS B.A. Skiff 29 July 1994

4056 PHOTOMETRY OF STARS IN THE FIELD OF VX TAURI B.A. Skiff 29 July 1994

4057 PHOTOMETRY OF STARS IN THE FIELD OF AQ AURIGAE B.A. Skiff 1 August 1994

4058 PHOTOMETRY OF STARS IN THE FIELD OF R AURIGAE B.A. Skiff 1 August 1994 4059 THE OBSERVATION OF SUPERHUMPS IN AY LYRAE D. Nogami, C. Kunjaya, T. Kato, R. Hirata 8 August 1994

4060 NEW PHOTOELECTRIC LIGHT CURVES OF VZ CANUM VENATICORUM G. Shenghong, L. Quingyao, Y. Yulan, W. Bi, H. Zhankui 8 August 1994

4061 NEW TIMES OF MINIMUM FOR V444 CYGNI J.A. Eaton, G.W. Henry 11 August 1994

4062 1993 BVRI PHOTOMETRY OF BH VIRGINIS P.A. Heckert, D.L. Summers 11 August 1994

4063 CHROMOSPHERIC INACTIVITY OF delta CORONAE BOREALIS IN 1991-93 J.D. Fernie ERRATUM E. Poretti 11 August 1994

4064 HIC 83921: A NEW PULSATING STAR IN HERCULES M. Aluigi, G. Galli, A. Gaspani 12 August 1994

4065 PHOTOMETRY OF STARS IN THE FIELD OF V431 ORIONIS B.A. Skiff 12 August 1994

4066 PHOTOMETRY OF THE ACTIVE STARS HD127535 AND HD202077 K.G. Strassmeier, E. Paunzen, P. North 12 August 1994

4067 A DIRECTORY OF COMPARISON STARS IN IBVS M. Morel 15 August 1994

4068 DETECTION OF VARIABILITY IN HD168947 E. Paunzen, W.W. Weiss, P. North 16 August 1994

4069 DISCOVERY OF PULSATION IN THE lambda Boo STAR HD111786 R. Kuschnig, E. Paunzen, W.W. Weiss 16 August 1994

4070 HD183324, A PULSATING lambda Boo STAR? R. Kuschnig, E. Paunzen, W.W. Weiss 16 August 1994

4071 PHOTOMETRIC PERIOD OF THE SUSPECTED DELTA SCUTI-TYPE STAR IOTA BOOTIS J. Gal, K. Szatmary, J. Vinko 17 August 1994

4072 SPECTROSCOPY OF FAINT CATACLYSMIC VARIABLES I. S.B. Howell, J. Liebert, K.O. Mason 18 August 1994

4073 SPECTROSCOPY OF FAINT CATACLYSMIC VARIABLES II. S.B. Howell, J. Liebert 18 August 1994 4074 SPECTROSCOPY OF FAINT CATACLYSMIC VARIABLES III. S.B. Howell, J. Liebert, R.M. Wagner 18 August 1994

4075 A NEW EPHEMERIS FOR UZ For G. Ramsay 24 August 1994

4076 NEW LIGHT CURVES AND PERIOD OF BV ERIDANI Gu Shenghong, L. Qingyao, Y. Yulan, Z. Zhousheng 25 August 1994

4077 PERIOD CHANGE OF delta Sct STAR HD79889 Liu Zhongli, J. Shiyang 31 August 1994

4078 NEW PERIOD AND PERIOD CHANGE OF EU HYDRAE Gu Shenghong 1 September 1994

4079 THE PHOTOMETRIC PERIOD OF THE OLD NOVA V368 AQUILAE M.P. Diaz, A. Bruch 1 September 1994

4080 UBVR PHOTOMETRY OF THE SYMBIOTIC STAR AG Dra IN ITS 1994 OUTBURST A. Skopal, D. Chochol 2 September 1994

4081 UBV PHOTOMETRY OF FY Per R. Zamanov, V. Zamanova 5 September 1994

4082 PHOTOELECTRIC OBSERVATIONS OF GR TAURI Min-jun Fang, Di-sheng Zhai, Zhen-don Gao, Rong-xian Zhang, Ji-tong Zhang, Xiao-bin Zhang 13 September 1994

4083 PHOTOMETRY OF THE ECLIPSING BINARY FK ORIONIS M. Zakirov 13 September 1994

4084 PHOTOMETRY OF THE SHORT PERIOD ECLIPSING BINARY FR ORIONIS M. Zakirov 13 September 1994

4085 PHOTOELECTRIC OBSERVATIONS OF VV Ori IN R AND I K. Arai 14 September 1994

4086 FURTHER PHOTOELECTRIC OBSERVATIONS OF VW Cep IN R AND I K. Arai 14 September 1994

4087 V397 Per IS MOST PROBABLY NOT VARIABLE U. Bastian, E. Jung 14 September 1994

4088 UBVR PHOTOMETRY OF THE ECLIPSING BINARY FH ORIONIS M. Zakirov 19 September 1994 4089 NEW PHOTOELECTRIC OBSERVATIONS AND PERIOD OF RS LEPORIS Gu Shenghong, L. Quingyao, Y. Yulan, W. Bi, H. Zhankui 19 September 1994

4090 MWC147: A SUSPECT OF A PRE-MAIN SEQUENCE S.L.A. Vieira, N.C.S. Cunha 19 September 1994

4091 IS GLIESE 410 OR BD+23d2297 THE ? R.D. Jeffries, D. Bertram, B.R. Spurgeon 20 September 1994

4092 CZ Cnc - A DWARF M FLARE STAR J. Greiner, C. Motch 20 September 1994

4093 OPTICAL VARIABILITY IN SAO 20517 AND ITS POSSIBLE IDENTIFICATION AS AN X-RAY SOURCE B. Martin, D.P. Hube, E. Steinbring, S. Cartledge 28 September 1994

4094 MULTIPERIODIC PHOTOMETRIC VARIATIONS OF HD 210111 AND SUSPECTED VARIABILITY OF HD 210049 E. Paunzen, G. Handler, W.W. Weiss, P. North 30 September 1994

4095 A NEW Be PHASE OF PLEIONE D. Ballereau, J. Chauville, J. Zorec 3 October 1994

4096 REVISED EPHEMERIS OF THE SYMBIOTIC BINARY AG Dra A. Skopal 3 October 1994

4097 PHOTOELECTRIC MINIMA OF ECLIPSING BINARIES Dalibor Hanzl 3 October 1994

4098 NEW PHOTOELECTRIC OBSERVATIONS FOR HL AURIGAE Rong-Xian Zhang, Min-jun Fang, Ji-tong Zhang, Di-sheng Zhai 11 October 1994

4099 PHOTOELECTRIC OBSERVATIONS OF EP AURIGAE Rong-xian Zhang, Ji-tong Zhang, Di-sheng Zhai 11 October 1994

4100 CIRCULAR POLARIMETRIC OBSERVATIONS OF THE MAGNETIC CV 1H1752+081 Gavin Ramsay, Mark Cropper 12 October 1994

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

September

HU ISSN

OPTICAL VARIABILITY IN SAO AND ITS

POSSIBLE IDENTIFICATION AS AN XRAY SOURCE

During a recent campaign to observe the massive eclipsing binary system HD

h m s 

the eld star SAO  was used as one of com

parison stars These observations reveal that SAO is variable with a variation of

ab out mag in the V passband Figure illustrates the photometric variation with

resp ect to SAO during a two month p erio d from July through August

d

Figure shows the same data phased with a p erio d of : The star SAO

h m s 

:  has b een used as the principal comparison star and

h m s 

SAO :  as a check star in these observations Data

have thus far b een obtained using The Kings University College Observatory CCD pho

tometer on a m telescop e and the University of Alb erta Devon Observatory two

channel photometer attached to the m telescop e The data as presented have not

b een transformed to the standard UBV system

SAO may b e an xray source It can b e tentatively identied with the nal source

listed by Helfand and Caillault and coincides with a weak unresolved source on

plate of The Eistein Observatory Catalog of IPC XRay Sources Bidelman

private communicatio suggests a sp ectral type of KIV based on examination of

a contaminated sp ectrum on an ob jective prism plate This and the light curve shown

in Figure lead us to suggest that SAO is either an RS CVn or ellipsoidal binary

system The relatively high incidence of transient xray source at high galactic latitude

Garcia et al lends credence to the suggestion that SAO is an RS CVn

Figure

V lter light curve for SAO covering a two month span The solid curve represents

a simple sinusoidal t to data Observations made on TKUC CCD and m reector

Figure Light curve of observation shown in Figure phased with a p erio d of

days Solid line shows the t provided by the sum of the rst four Fourier comp onents

system At the same time evidence of ellipsoidal variation is provided by a leastsquares

t of the rst Fourier comp onents to the light curve The variation can b e describ ed

via

vsin s in cos cos 

when v is represented as a function of phase  The standard error in the Fourier

co ecients is on the order of mag The residual error in the Fourier t is approx

imately mag which is typical of the scatter in the observations The dominance of

the cos term supp orts the suggestion that SAO is an ellipsoidal binary system

The authors are obtaining additional multicolour UBVR photometric data Sp ectro

scopic data are b eing obtained Dominion Astrophysical Observatory Victoria A complete

discussion of this system will b e published elsewhere We thank Dr W Bidelman for a

very informative discussion ab out this star and related matters

B MARTIN DP HUBE

The Kings University College E STEINBRING

th Street S CARTLEDGE

Edmonton ABCA Department of Physics

TB H

University of Alb erta

bmartinkingsuabca

Edmonton ABCA

TG J

References

Bidelman W private communication

Garcia M et al Astrophys J L

Helfand D J and JP Caillault Astrophys J

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

September

HU ISSN

MULTIPERIODIC PHOTOMETRIC VARIATIONS OF HD

AND SUSPECTED VARIABILITY OF HD

We present time series of our observations of a new variable Bo o star HD m

V

which is classied as kAhAmAV Bo o by Gray and Corbally Bo otis

stars are a group of metal p o or Population I stars Weiss et al with broad and often

shallow hydrogen lines which are probably caused by a gas shell There are indications

for such a gas shell also for HD St urenburg An abundance analysis for

that star St urenburg gave a metal deciency of ab out a factor of compared to

the Sun

Our observations were part of a survey for pulsation among Bo o stars Paunzen Weiss

and North Kuschnig Paunzen and Weiss ab using the cm Swisstelescop e

at ESO La Silla with the Geneva photometer When variability of HD b ecame

evident in the raw data it was decided to observe this Bo o type star as frequently as

p ossible PN and EP used HD m A IVnn as rst comparison star during

V

nights distributed over weeks and in addition in one of these nights HD m

V

F V as a second comparison

HD A quick lo ok at the extinction corrected dierential instrumental mag

nitudes Fig indicates already multiperio dic variations for this star An amplitude

sp ectrum computed with a singlefrequency Fourier technique for unequally spaced data

program PERIOD Breger indicates the presence of at least pulsation frequencies

Fig second panel The frequencies with the largest amplitudes are f cd and

1

f cd which could b e inuenced by a cd aliasing In any case this solution

2

is rather formal and serves only as a guideline for the relevant frequency range

A simultaneous frequency t to the observations of HD based on the lowest

residuals after a stepbystep prewhitening results in a scatter of mmag which is

almost twice the value for the extinction corrected observations of the comparison star

HD We thus conclude that probably several mo des may b e excited in HD

A problem for the frequency analysis is the p o or duty cycle of only of our single

site data However it is quite obvious that HD is a promising candidate for an

international photometric observing campaign

The calibration Crawford Philip Relyea for FeH of uv by

photometry applied to the indices listed by Hauck Mermilliod for HD

results in M T K and log g These parameters give Qvalues

v ef f

ranging from to d based on

log Q log T log g M log P

ef f bol

According to pulsation mo dels Fitch such Qvalues indicate pulsation in the second

to fth overtone

HD Our present analysis dep ends on the constancy of the primary compari

son HD except for one night where a second comparison star has b een observed

Figure HD HD in GenevaV residuals to nightmean

Figure Amplitude sp ectrum b ottom panel and sp ectral window of the data of Fig

Figure Amplitude sp ectrum of the extinction corrected GenevaV photometry

of HD

In order to demonstrate the validity of this assumption we show the amplitude sp ectrum

of our extinction corrected instrumental data of HD in Fig The highest noise

p eaks for frequencies larger than cd show amplitudes of mmag However a p eak

at cd with an amplitude of mmag clearly exceeds the noise level This p eak also

app ears in the amplitude sp ectrum of the dierential HD HD data but

not in the HD data alone The dierential magnitudes of the two comparison stars

HD HD have mmag

We therefore cannot exclude variability of our primary comparison star HD

with a p erio d of ab out hours but cannot pro of this claim with the second comparison

star However it is quite safe to attribute the variability in the dierential photometry

of our Bo o star in the to cd frequency domain Figs and to HD and

not to the comparison star

Pulsation of HD would b e remarkable b ecause eective temp erature and abso

lute magnitude T K M based on Stromgren photometry lo cate this

ef f v

star outside the Scuti instability strip On the other hand the hot b order of this insta

bility strip is not very well dened and a shift towards hotter temp eratures was recently

prop osed by Ro driguez et al

Conclusions We discovered multiperio dic variability in the Bo o star HD

and cannot rule out variability of HD The frequency sp ectrum of HD is

complicated and only a suciently long multisite campaign weeks or more will allow

a successful resolution HD is a promising candidate for applying asteroseismic

techniques and thus to investigate the problem of the origin of Bo otis stars Another

interesting case is HD Kuschnig et al a We also encourage further obser

vations of HD

Acknowledgement This research was supp orted by the Ho chschuljubilaumsstiftung

der Stadt Wien and by the Swiss National Foundation for Scientic Research

E PAUNZEN

G HANDLER

W W WEISS

Institut f ur Astronomie

T urkenschanzstr

A Wien Austria

NAMEASTROASTUNIVIEACAT Email LAST

P NORTH

Institut dastronomie de lUniversite

de Lausanne

CH ChavannesdesBois Switzerland

Email NORTHOBSUNIGECH

References

Breger M Communications in Asteroseismology University of Vienna

Crawford D L AJ

Fitch W S ApJ

Gray R O Corbally C J AJ

Hauck B Mermilliod M AAS

Kuschnig R Paunzen E Weiss W W a IBVS No

Kuschnig R Paunzen E Weiss W W b IBVS No

Paunzen E Weiss W W North P IBVS No

Philip A G D Relyea L J AJ

Ro driguez E Lopez de Co ca P Rolland A Garrido R Costa V AAS

St urenburg S AA

Weiss W W Paunzen E Kuschnig R Schneider H AA

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

Octob er

HU ISSN

A NEW Be PHASE OF PLEIONE

The well known Beshell star Pleione BU Tauri HD BIVVe vsini

kms passed through several B Be and Beshell phases since The last Beshell

phase b egan in Delplace and Hub ert Hirata and Kogure reached a

maximum around and entered a decrease in Ballereau et al In

emission lines were strong shell lines almost completely disapp eared with the exception

of FeII multiplet No while the photospheric comp onent of Balmer lines weak and

shallow in b ecame deep er and wider Ballereau et al The disapp earance

of the shell lines go es along with the increase of their negative RVs higher terms of

the Balmer lines and metallic ions which indicates that the surrounding envelope of

gas gradually expands in space over several Recent observations of H emission

comp onent made by Menchenkova and Luthardt conrm the gradual increase of

its equivalent width until and the faintness of the central reversal

On Aug we obtained the H and FeII A line proles of Pleione with the

AURELIE receptor attached to the coudefo cus of the m telescop e of HauteProvence

Observatory Figure The parameters of the sp ectrum are as follows

Resolution

Signal to noise ratioSN

Recorded sp ectral wavelength range A

The sp ectroscopic parameters measured on the H and FeII emission proles radial

velocities RV in kms intensities I in fraction of stellar continuum intensity give the

following results

H

Violet p eak RV I central reversal red p eak

VR emission p eak separation e kms RV and total width of the emission

line at the junction with the photospheric prole at the intensity level

at the intensity level

FeIIA

Violet p eak RV I central reversal red p eak

VR ekms

From comparison of the present data with those obtained these last years several

remarks can b e emphasized

The decrease and vanishing of shell lines on Balmer series and metallic ion sp ectra si

multaneously with the strengthening of the emission comp onents observed since until

the nineties are monotonic phenomena which translate the gradual spatial development

of the surrounding emittingabsorbing envelope of Pleione

Figure Normalized intensity tracing of the H and FeIIA

lines of Pleione on Aug The vertical bars give the rest wavelengths

of each line

The progressively negative RVs of emissionshellabsorption lines of the optical sp ec

trum from indicate the onset of a new instability which leads to a gradual expansion

of the envelope as well in the equatorial plane then as probably vertically on b oth sides

of this plane In the RVs of the absorptionlike remaining depression in the H

and FeII lines Figure resp ectively and kms suggest a rather rapid expan

sion while b efore during the quiet and strong shell phase they were small with

p erio dic variations Ballereau et al

Measurements of p eak separation e on H obtained by ourselves since the sev

enties and used in Huangs formula in the case of a Keplerian rotational mo

tion in the envelope p ermit to obtain the outer radius of the H emitting envelope

RH R The H emission

prole of Menchenkova and Luthard has eA which gives RH R

All these data conrm the expanding movement of the envelope of Pleione

The fading of the Balmer photospheric proles during the quiet and strong shell

phase b efore and their gradual strengthening after show that at rst the envelope

is probably compact co ol and optically thick while its sp ectrum dominates the one of

the underlying B star It lo oks the one of an AF star The expansion of the envelope

on b oth sides of the equatorial plane makes the central star more visible which can also

explain the reapp earance of the Balmer photospheric sp ectrum of Pleione

The equivalent width of the emission in the H line increases progressively WH

em

A A A

The p eak separation of the FeII emission line in kms gives an outer radius

of the FeII emitting disc of R This indicates that this disc is nearer to the stellar

surface than the H emitting disc as generally observed in Be star envelopes

All these changes in the structure of the Pleione shell claim in favour of the phase

change mo del prop osed by Kogure where the envelope resp onsible for a shell phase

should b e a compact thinthick disclike one which has to expand to transform itself into

an extended spheroidaldoughnut shap e to pro duce a sp ectrum characteristic of a Be

phase The same type of mo del was also prop osed by Zorec and Briot to explain

the photometric variations during the phase changes of Be stars

D BALLEREAU

J CHAUVILLE

Observatoire de Paris

section de Meudon

place Jules Janssen

Meudon principal cedex

France

J ZOREC

Institut dastrophysique de Paris

bis

b oulevard Arago

Paris

France

References

Ballereau D Chauville J Mekkas A AAS

Ballereau D Chauville J Zorec J International Conference Circumstellar

Matter held at Edinburgh Scotland Aug thSep nd

Delplace AM Hub ert H C R Acad Sc Paris SerieB p

Hirata R Kogure T PASJ

Huang SS ApJ

Kogure T ASS

Menchenkova E V Luthardt R IBVS No

Zorec J Briot D AA

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

Octob er

HU ISSN

REVISED EPHEMERIS OF THE SYMBIOTIC BINARY AG Dra

AG Dra is one of the most intensively monitored symbiotic stars Its lightcurve LC

has b een studied photographically since by Robinson Until the con

tinuum of AG Dra had displayed a quiescent stage but afterwards several eruptions have

b een observed From multicolour photo electric observations were p erformed by

many authors The p erio dic wavelike variation in the optical continuum was observed

during quiescent stages It is largest at the ultraviolet bands U  u  mag and

b ecomes smaller with increasing wavelength by comparison B  and V 

eg Kaler Meinunger Meinunger from his U data established for

the rst time a day p erio d with a U ep o ch at JD Consistence of this

max

p erio d with the orbital p erio d of the binary was conrmed by variations

of the co ol comp onent measured by Garcia Kenyon In accord with the Garcia

Kenyons solution of the sp ectroscopic orbit the minima in the U band corresp ond to

the sp ectroscopic conjunction with the co ol comp onent in front Recent UBV photome

try conrmed this p erio dic variation The data were mostly collected in our campaigns

pap ers Hric et al Skopal et al

The aim of this contribution is to determine an ephemeris for the minima in the

ultraviolet domain On this account we constructed the U u LC from all the available

data in the literature Dierential values of magnitudes in u published by Kaler

and Kaler et al were shifted by mag to b e approximately consistent with the

stars brightness in the U band The LC is shown in Fig It covers the p erio d from

March to September with the nine minima in the quiescence Their p ositions

were determined by the least squares tting of the second degree p olynom to the data

under consideration Results are summarized in Table The linear regression of the

minima p ositions at the ep o chs gives their ephemeris as

JD U    E

min

The minimum at JD was not used for determination of this ephemeris b ecause

of its worse denition and a larger shift in its p osition with resp ect to the other minima

The maximum uncertainties JD d and P d were determined according to

relations P E Minn and JD Minn in which n is the number of the

minima used For the uncertainty in the p osition of the minimum under consideration

Min we adopted the corresp onding O C value b ecause of assuming a constant orbital

p erio d and the O C values are larger than the uncertainties in the p osition of individual

minima The minima indicated photographically in the historical LC for example at

  Sharov  Luthardt agree well with those predicted by the ephemeris

Figure Compiled U u light curve of AG Dra

Table

Ep o ch JD O JD C O C

Min Min



















The O C diagram is shown in Fig Dierences b etween the observed and computed

p ositions of the minima are often far larger than the uncertainty of their determination

This reects the fact that the individual minima dier from each other b oth in the shap e

and the p osition cf Fig Such b ehaviour cannot b e ascrib ed to a reection eect

b ecause this eect can pro duce only a strictly regular shap e of LCs Moreover due

to a relatively small radius of the co ol comp onent R as for its sp ectral type of

KI I I a very small fraction of the hot comp onent radiation approximately

for the separation of the comp onents of R will irradiate the facing co ol comp onent

hemisphere which is not sucient to give rise of the mag reection eect cf Skopal

It is suggested that the circumstellar matter lo cated in the binary within the

common p otentials due to an outbursting activity of the hot comp onent is resp onsible

for such a wavelike variation in the optical continuum cf Skopal et al

Figure

OC diagram of the minima in the U u light curve of AG Dra

A SKOPAL

Astronomical Institute

Slovak Academy of Sciences

Tatranska Lomnica

Slovakia

References

Garcia MR Kenyon SJ In Mikola jewska et al eds The Symbiotic Phe

nomenon IAU Coll Kluwer Dordrecht p

Hric L Skopal A Urban Z et al Contr Astron Obs Skalnate Pleso

Hric L Skopal A Urban Z et al Contr Astron Obs Skalnate Pleso

Hric L Skopal A Cho chol D et al Contr Astron Obs Skalnate Pleso

Kaler JB AJ

Kaler JB Sto ehr CA Hartkopf WI et al AJ

Luthardt R Mitt Veranderl Sterne No

Meinunger L IBVS No

Robinson L Peremennye Zvezdy

Sharov AS Peremennye Zvezdy

Skopal A AA

Skopal A Hric L Urban Z et al Contr Astron Obs Skalnate Pleso

Skopal A Hric L Cho chol D et al Contr Astron Obs Skalnate Pleso

in press

Skopal A Vittone A Errico L AASS

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

Octob er

HU ISSN

PHOTOELECTRIC MINIMA OF ECLIPSING BINARIES

The following Table gives the photo elecric minima obtained in the years at

the N Cop ernicus Observatory and Planetarium in Brno Czech Republic by means of

the Nasmyth type m telescop e

The telescop e was used with a single channel photometer and EMI B photomul

tiplier Measurements were made in the UBVsystem The integration time of one mea

surement was ten second

The times of minimum brightness and their standard deviation were determined by

Kweevan Woerdens metho d The name of star the name of the lter helio centric

time of minima standard deviation dierent values of OC and abbreviations of the

observerss name are given in Table The abbreviations in the column Observer

means

DH Dalib or Hanzl EN Eva Neureiterova PH Petr Hajek TH Tomas Hudecek MN

Martin NavratilMZ Miloslav Zejda

Data for calculating the OC residuals have b een taken from the following literature

OCI SAC Krakow

OCI GCVS Moscow

Table

Name JD hel err OCI OCI I Obs

RT And V s MN

V MN

B MN

U MN

V MN

B MN

U MN

DS And V DH

B DH

RX Ari V DH

B DH

TT Aur V DH

B DH

U DH

BF Aur V s DHPH

B s DHPH

U s DHPH

VW Cep V EN

B EN

GS Cep V s DH

B s DH

V DH

B DH

V DH

B DH

Table cont

Name JD hel err OCI OCI I Obs

GS Cep V s DH

B s DH

V Cyg V DHTH

B DHTH

TT Her V DHTH

B DHTH

V DH

B DH

V Oph V DHTH

B DHTH

V Oph V DH

B DH

V DH

B DH

FT Ori V DHEN

B DHEN

U DHEN

V Ori V DH

B DH

GP Peg B MZDH

IU Per V DH

B DH

U DH

GR Tau V DH

B DH

BU Vul V DH

B DH

Moments of the secondary minima are lab elled by s As far as the data for calculating

the time of the secondary minima are not given in the ab ove mentioned literature we use

the phase for calculating the OC of the secondary minima the secondary minimum

is supp osed to b e in midphase b etween the primary ones

In case the elements in b oth sources are equal the OCs are also equal this is indi

cated by the sign The GCSV p erio d of GS Cep is denitely wrong so corresp onding

OC values are not given

Dalib or HANZL

N Cop ernicus Observatory

and Planetarium

Kravi hora

Brno

Czech Republic

email HANZLvmicsmunicz

References

GCVS Moscow

Kwee K K and van Woerden H Bul l Astron Inst Neth No SAC Krakow

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

Octob er

HU ISSN

NEW PHOTOELECTRIC OBSERVATIONS FOR HL AURIGAE

HL Aur is an eclipsing binary system It was rst observed by Pfau and Kipp en

hahn gave a photographic light curve and a series of time of minima Tsesevitch

Lo cher Quester Frank Fernandes Moschner and

Kleikamp published some times of minima Most of them were obtained

by visual or photographic observations except for the one given by Fernandes based on

photo electric observation

The star was observed photo electrically on nights in winter season in and

resp ectively by using the cm reector at Xinglong station of Beijing Astronomical

Observatory

The nding chart for comparison and check stars is shown in Figure All observational

data were corrected for dierential atmospheric extinction and transformed into Johnson

standard system

Using KweeVan Woerden metho d six photo electric times of minima were determined

see Table The light curves of HL Aur given in Figure consisting of

m

individual observations show that the depth of the primary minimum is : and that

m

of the secondary is : and a little asymmetry b etween Max I and Max II may b e

discovered

We derived a new improved ephemeris by using all the recent times of minima as

follows

d

MinIHJD : E

 

From the OC diagram the p erio d of HL Aur is nearly constant over the past years

Figure The nding chart of HL Aur

   

BD BD BD BD

Figure The light curves of HL Aur in BV colours

Table New times of minima

JDHel colour Min me

V II

B II

V I

B I

V I

B I

V II

V II

B II

V I

B I

RongXian ZHANG

Minjun FANG

Jitong ZHANG

Disheng ZHAI

Bejing Astronomical Observatory

Chinese Academy of Sciences

Beijing China

References

Fernandes M BAVMitteilungen No

Frank P BAVMitteilungen No

Kipp enhahn R Astron Nach

Lo cher K BBSAG No

Moschner W Kleikamp W BAVMitteilungen No

Moschner W Kleikamp W BAVMitteilungen No

Pfau W MVS Sonneb erg No

Quester W BAVMitteilungen No

Tsesevitch V P Astron Circular No

COMMISSIONS AND OF THE IAU

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Number

Konkoly Observatory

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Octob er

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PHOTOELECTRIC OBSERVATIONS OF EP AURIGAE

EP Aur was discovered to b e an eclipsing binary by Homeister and is a

d

Lyr type binary with a p erio d of : Tsesevitch gave a complete light curve

together with times of photographic minima but no more attention was paid to this

star in past years Recently Frank Vielmetter Moschner and Kleikamp

Agerer published some times of minima for this star among which only

one was photo electric observation Agerer the other were photographic or visual

observations

This star was included as one of short p erio d Lyr binaries of our observational

programme and observed by using the cm reector at Xinglong station of Beijing

Astronomical Observatory from December to February

Comparison and check stars are very near to the binary The nding chart is shown in

Figure All individual observational were corrected for dierential atmospheric extinc

tion and transformed into standard UBV system A total of observations in each B

and V colour were obtained including one primary and three secondary times of minima

The light curves in BV bands are shown in Figure From the light curves we can derive

m m

the depth of the primary minimum to b e ab out : and that of the secondary ab out :

The times of minima were estimated by using KweeVan Woerden metho d A new

ephemeris based on our new times of minima together with published minima in literature

is derived as follows

d

MinIHJD : E

 

Table I New times of minima of EP Aur

JDHel colour Min me

V I

B I

V II

B II

V II

B II

V II

B II

Figure The nding chart of EP Aur

    

BD BD BD BD BD

c comparison star ch check star

Figure The light curves of EP Aur in BV colours

From the OC diagram the p erio d of this star is nearly constant The times of

minima collected for this star were not enough to cover all the imp ortant parts of the

OC diagram so the conclusion has to b e conrmed

A further analysis of the light curves is in progress

Rongxian ZHANG

Jitong ZHANG

Disheng ZHAI

Beijing Astronomical Observatory

Chinese Academy of Sciences

Beijing China

References

Agerer F BAVMitteilungen No

Frank P BAVMitteilungen No

Homeister C Astron Nach Nr

Homeister C Sonn Vero

Moschner W and Kleikamp W BAVMitteilungen No

Tsesevitch V P Odessa Isv

Vielmetter H BAVMitteilungen No

COMMISSIONS AND OF THE IAU

INFORMATION BULLETIN ON VARIABLE STARS

Number

Konkoly Observatory

Budap est

Octob er

HU ISSN

CIRCULAR POLARIMETRIC OBSERVATIONS OF THE

MAGNETIC CV H

H was discovered using the HEAO satellite and identied with an eclipsing

CV whose p erio d was mins Silb er et al Barwig Ritter Barnbantner

The eclipse is unusual in that the ingress to eclipse is more variable and twice as long as

the egress Silb er et al claim that the system has a small accretion disk with the

p ossibility that it is an intermediatepolar a close binary in which the primary is a mass

accreting with a magnetic eld strength B MG On the other hand

Barwig et al suggest that their observations are consistent with the ob ject b eing

an AM Her system a close binary in which the primary is a mass accreting white dwarf

whose spin p erio d is coupled with the orbital p erio d and has a magnetic eld strength

B MG suciently strong to prevent the formation of an accretion disc The AM

Her systems show strongly variable circular p olarisation while the intermediatepolars

have generally undetectable levels of circular p olarisation with the exception of BG CMi

Penning Schmidt Lieb ert and RE Rosen Mittaz Hakala

These have detectable but lower values of circular p olarisation than found in AM Her

systems and inferred magnetic eld strengths at the lower end of the range found for

AM Hers H was observed sp ectroscopically during a low intensity state and

was found to have a magnetic eld strength B MG Ferrario et al Such a

low magnetic eld strength suggests that the ob ject would exhibit low levels of circular

p olarisation To conrm this we obtained circular p olarimetry of H covering

two orbital cycles

We made observations of H at two separate ep o chs using the Anglo Aus

tralian Telescope The Faint Ob ject Polarimeter was used with a Tektronix CCD as the

detector and an OG lter A Both photometry and circular p olarisation

data were obtained on July for mins and mins the following day The

exp osures were sec in duration The data were reduced as describ ed by Cropp er et al

Figures show the photometric and p olarimetric data folded on the ephemeris of

Barwig et al The photometric light curve is similar in shap e to that rep orted by

Barwig et al and Silb er et al However the main p oint of interest is the

very low level of circular p olarisation Although a p ositive level of circular p olarisation

was recorded on each night the observations of unp olarised standard stars using the same

instrumental conguration are inadequate for ruling out the p ossibility that this low level

of p olarisation is instrumental in origin This view is strengthened by the fact that the

phased circular p olarisation is dierent on the two nights We therefore conclude that

any circular p olarisation in H is 

These results coupled with the low magnetic eld strength determined by Ferrario et

al suggest that H is not in fact an AM Her star but is more likely to

b e an intermediatepolar

Figure Circular p olarisation and photometric data folded on the ephemeris

of Barwig et al taken on July with the OG lter

Figure Circular p olarisation and photometric data folded on the ephemeris of

Barwig et al taken on July with the OG lter

Gavin RAMSAY

Mark CROPPER

Mullard Space Science Lab

University College London

Dorking Surrey RH NT

UK

References

Barwig H Ritter H Barnbantner O AA

Cropp er M Bailey J Wickramasinghe D T Ferrario L MNRAS P

Ferrario L Wickramasinghe D Bailey J Buckley D in press

Penning W R Schmidt G D Lieb ert J ApJ

Rosen S R Mittaz J P D Hakala P J MNRAS

Silb er A D Remillard R A Horne K Bradt H V ApJ