Among the Intrinsic Variables, the RV Tauri Stars Days
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Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
Spectroscopy of Variable Stars
Spectroscopy of Variable Stars Steve B. Howell and Travis A. Rector The National Optical Astronomy Observatory 950 N. Cherry Ave. Tucson, AZ 85719 USA Introduction A Note from the Authors The goal of this project is to determine the physical characteristics of variable stars (e.g., temperature, radius and luminosity) by analyzing spectra and photometric observations that span several years. The project was originally developed as a The 2.1-meter telescope and research project for teachers participating in the NOAO TLRBSE program. Coudé Feed spectrograph at Kitt Peak National Observatory in Ari- Please note that it is assumed that the instructor and students are familiar with the zona. The 2.1-meter telescope is concepts of photometry and spectroscopy as it is used in astronomy, as well as inside the white dome. The Coudé stellar classification and stellar evolution. This document is an incomplete source Feed spectrograph is in the right of information on these topics, so further study is encouraged. In particular, the half of the building. It also uses “Stellar Spectroscopy” document will be useful for learning how to analyze the the white tower on the right. spectrum of a star. Prerequisites To be able to do this research project, students should have a basic understanding of the following concepts: • Spectroscopy and photometry in astronomy • Stellar evolution • Stellar classification • Inverse-square law and Stefan’s law The control room for the Coudé Description of the Data Feed spectrograph. The spec- trograph is operated by the two The spectra used in this project were obtained with the Coudé Feed telescopes computers on the left. -
Variable Star Classification and Light Curves Manual
Variable Star Classification and Light Curves An AAVSO course for the Carolyn Hurless Online Institute for Continuing Education in Astronomy (CHOICE) This is copyrighted material meant only for official enrollees in this online course. Do not share this document with others. Please do not quote from it without prior permission from the AAVSO. Table of Contents Course Description and Requirements for Completion Chapter One- 1. Introduction . What are variable stars? . The first known variable stars 2. Variable Star Names . Constellation names . Greek letters (Bayer letters) . GCVS naming scheme . Other naming conventions . Naming variable star types 3. The Main Types of variability Extrinsic . Eclipsing . Rotating . Microlensing Intrinsic . Pulsating . Eruptive . Cataclysmic . X-Ray 4. The Variability Tree Chapter Two- 1. Rotating Variables . The Sun . BY Dra stars . RS CVn stars . Rotating ellipsoidal variables 2. Eclipsing Variables . EA . EB . EW . EP . Roche Lobes 1 Chapter Three- 1. Pulsating Variables . Classical Cepheids . Type II Cepheids . RV Tau stars . Delta Sct stars . RR Lyr stars . Miras . Semi-regular stars 2. Eruptive Variables . Young Stellar Objects . T Tau stars . FUOrs . EXOrs . UXOrs . UV Cet stars . Gamma Cas stars . S Dor stars . R CrB stars Chapter Four- 1. Cataclysmic Variables . Dwarf Novae . Novae . Recurrent Novae . Magnetic CVs . Symbiotic Variables . Supernovae 2. Other Variables . Gamma-Ray Bursters . Active Galactic Nuclei 2 Course Description and Requirements for Completion This course is an overview of the types of variable stars most commonly observed by AAVSO observers. We discuss the physical processes behind what makes each type variable and how this is demonstrated in their light curves. Variable star names and nomenclature are placed in a historical context to aid in understanding today’s classification scheme. -
121012-AAS-221 Program-14-ALL, Page 253 @ Preflight
221ST MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY 6-10 January 2013 LONG BEACH, CALIFORNIA Scientific sessions will be held at the: Long Beach Convention Center 300 E. Ocean Blvd. COUNCIL.......................... 2 Long Beach, CA 90802 AAS Paper Sorters EXHIBITORS..................... 4 Aubra Anthony ATTENDEE Alan Boss SERVICES.......................... 9 Blaise Canzian Joanna Corby SCHEDULE.....................12 Rupert Croft Shantanu Desai SATURDAY.....................28 Rick Fienberg Bernhard Fleck SUNDAY..........................30 Erika Grundstrom Nimish P. Hathi MONDAY........................37 Ann Hornschemeier Suzanne H. Jacoby TUESDAY........................98 Bethany Johns Sebastien Lepine WEDNESDAY.............. 158 Katharina Lodders Kevin Marvel THURSDAY.................. 213 Karen Masters Bryan Miller AUTHOR INDEX ........ 245 Nancy Morrison Judit Ries Michael Rutkowski Allyn Smith Joe Tenn Session Numbering Key 100’s Monday 200’s Tuesday 300’s Wednesday 400’s Thursday Sessions are numbered in the Program Book by day and time. Changes after 27 November 2012 are included only in the online program materials. 1 AAS Officers & Councilors Officers Councilors President (2012-2014) (2009-2012) David J. Helfand Quest Univ. Canada Edward F. Guinan Villanova Univ. [email protected] [email protected] PAST President (2012-2013) Patricia Knezek NOAO/WIYN Observatory Debra Elmegreen Vassar College [email protected] [email protected] Robert Mathieu Univ. of Wisconsin Vice President (2009-2015) [email protected] Paula Szkody University of Washington [email protected] (2011-2014) Bruce Balick Univ. of Washington Vice-President (2010-2013) [email protected] Nicholas B. Suntzeff Texas A&M Univ. suntzeff@aas.org Eileen D. Friel Boston Univ. [email protected] Vice President (2011-2014) Edward B. Churchwell Univ. of Wisconsin Angela Speck Univ. of Missouri [email protected] [email protected] Treasurer (2011-2014) (2012-2015) Hervey (Peter) Stockman STScI Nancy S. -
Gaia Data Release 2 Special Issue
A&A 623, A110 (2019) Astronomy https://doi.org/10.1051/0004-6361/201833304 & © ESO 2019 Astrophysics Gaia Data Release 2 Special issue Gaia Data Release 2 Variable stars in the colour-absolute magnitude diagram?,?? Gaia Collaboration, L. Eyer1, L. Rimoldini2, M. Audard1, R. I. Anderson3,1, K. Nienartowicz2, F. Glass1, O. Marchal4, M. Grenon1, N. Mowlavi1, B. Holl1, G. Clementini5, C. Aerts6,7, T. Mazeh8, D. W. Evans9, L. Szabados10, A. G. A. Brown11, A. Vallenari12, T. Prusti13, J. H. J. de Bruijne13, C. Babusiaux4,14, C. A. L. Bailer-Jones15, M. Biermann16, F. Jansen17, C. Jordi18, S. A. Klioner19, U. Lammers20, L. Lindegren21, X. Luri18, F. Mignard22, C. Panem23, D. Pourbaix24,25, S. Randich26, P. Sartoretti4, H. I. Siddiqui27, C. Soubiran28, F. van Leeuwen9, N. A. Walton9, F. Arenou4, U. Bastian16, M. Cropper29, R. Drimmel30, D. Katz4, M. G. Lattanzi30, J. Bakker20, C. Cacciari5, J. Castañeda18, L. Chaoul23, N. Cheek31, F. De Angeli9, C. Fabricius18, R. Guerra20, E. Masana18, R. Messineo32, P. Panuzzo4, J. Portell18, M. Riello9, G. M. Seabroke29, P. Tanga22, F. Thévenin22, G. Gracia-Abril33,16, G. Comoretto27, M. Garcia-Reinaldos20, D. Teyssier27, M. Altmann16,34, R. Andrae15, I. Bellas-Velidis35, K. Benson29, J. Berthier36, R. Blomme37, P. Burgess9, G. Busso9, B. Carry22,36, A. Cellino30, M. Clotet18, O. Creevey22, M. Davidson38, J. De Ridder6, L. Delchambre39, A. Dell’Oro26, C. Ducourant28, J. Fernández-Hernández40, M. Fouesneau15, Y. Frémat37, L. Galluccio22, M. García-Torres41, J. González-Núñez31,42, J. J. González-Vidal18, E. Gosset39,25, L. P. Guy2,43, J.-L. Halbwachs44, N. C. Hambly38, D. -
Inhaltsverzeichnis
Nachlass EDUARD SCHÖNFELD (1828-1891) Inhaltsverzeichnis Bearbeitet von Anne Hoffsümmer und Lea Korb Bonn, 2017 – 2018 zuletzt aktualisiert am 09.09.2020 Eduard Schönfeld wurde am 22.12.1828 in Hildburghausen geboren, wo er bis zu seinem Abitur 1847 die Schule besuchte. Er war Kind einer jüdischen Familie, trat jedoch nach seinem Schulabschluss dem evangelischen Glauben bei. Auf Anraten seines Vaters studierte Schönfeld zunächst Bauwesen, entschied sich aber nach kurzer Zeit für die Naturwissenschaften und begann, in Marburg bei dem Gauß-Schüler Christian Ludwig Gerling unter anderem Astronomie zu studieren. Nachdem Schönfeld auf einer Reise nach Bonn Bekanntschaft mit Friedrich Wilhelm August Argelander gemacht hatte, entschloss er sich, das Studium der Astronomie 1852 in Bonn fortzusetzen. Dort erhielt er schon ein Jahr später eine Stelle als Assistent, durch die er die Möglichkeit erhielt, gemeinsam mit Adalbert Krüger an der bekannten „Bonner Durchmusterung“, Argelanders großem Projekt, mitzuwirken. Mit einer Abhandlung über die Bahnelemente des Kleinplaneten Thetis promovierte Schönfeld 1854. Seine Habilitation folgte drei Jahre später. Eduard Schönfeld zog 1859 nach Mannheim, um dort die Stelle als Direktor der Mannheimer Sternwarte anzutreten. In der Mannheimer Zeit widmete er sich unter anderem der Bestimmung der Positionen von Nebelflecken mithilfe des Ringmikrometer. Eduard Schönfeld war Mitbegründer und Vorstandsmitglied der Astronomischen Gesellschaft sowie lange Jahre ihr Schriftführer und Herausgeber der Vierteljahrsschrift. Nach Argelanders Tod im Jahr 1875 übernahm Schönfeld dessen Stelle als Direktor der Bonner Sternwarte und ergänzte die Arbeit zur Bonner Durchmusterung, indem er die Bereiche -2°- -23° der südlichen Deklination erforschte. 1883 wurde er Geheimer Regierungsrat und war 1887/88 Rektor der Universität Bonn. -
1973Apj. . .185. .597D the Astrophysical Journal, 185:597-619
.597D The Astrophysical Journal, 185:597-619, 1973 October 15 .185. © 1973. The American Astronomical Society. All rights reserved. Printed in U.S.A. 1973ApJ. NEW OBSERVATIONS OF RV TAURI STARS David L. DuPuy* David Dunlap Observatory, University of Toronto, Richmond Hill, Ontario, Canada Received 1973 March 27 ABSTRACT New photoelectric and spectroscopic observations of RV Tauri stars have been obtained, and mean visual magnitudes and characteristics of the light and color curves have been derived. Most RV Tauri stars show rather irregular light curves, with successive cycles showing deviations up to several tenths of a magnitude. An analysis of the color excesses in ( F — i?) indicates the existence of reddening due to circumstellar material. Revised periods are suggested in a number of cases. Attempts were made to determine absolute magnitudes of RV Tauri stars by the following methods: (i) globular-cluster RV Tauri stars; (ii) mean secular and statistical parallaxes; (iii) the application of Wesselink’s method (which was unsuccessful); and (iv) luminosity classification spectrograms. A period-luminosity relation is evident. Absolute magnitude methods which depend on observa- tions of apparent magnitudes yield results averaging about 1.5 mag fainter than those methods based on other arguments. This difference is attributed to mostly nonselective absorption in circumstellar material and leads to visual absolute magnitudes of —5 to —6 inside the circum- stellar shells. Subject headings: circumstellar shells — luminosities — RV Tauri stars I. INTRODUCTION The class of RV Tauri stars comprises about 100 supergiant stars with unique characteristics of variability. Their light curves display two unequal minima, making uncertain which is the more physically significant period : the interval between succes- sive maxima or minima (single period), or the interval between successive deep minima (double period). -
A High Contrast Survey for Extrasolar Giant Planets with the Simultaneous Differential Imager (SDI)
A High Contrast Survey for Extrasolar Giant Planets with the Simultaneous Differential Imager (SDI) Item Type text; Electronic Dissertation Authors Biller, Beth Alison Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 03/10/2021 23:58:44 Link to Item http://hdl.handle.net/10150/194542 A HIGH CONTRAST SURVEY FOR EXTRASOLAR GIANT PLANETS WITH THE SIMULTANEOUS DIFFERENTIAL IMAGER (SDI) by Beth Alison Biller A Dissertation Submitted to the Faculty of the DEPARTMENT OF ASTRONOMY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2 0 0 7 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dis- sertation prepared by Beth Alison Biller entitled “A High Contrast Survey for Extrasolar Giant Planets with the Simultaneous Differential Imager (SDI)” and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy. Date: June 29, 2007 Laird Close Date: June 29, 2007 Don McCarthy Date: June 29, 2007 John Bieging Date: June 29, 2007 Glenn Schneider Final approval and acceptance of this dissertation is contingent upon the candi- date's submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. -
Pulsating Variable Stars and the Hertzsprung-Russell Diagram
- !% ! $1!%" % Studying intrinsically pulsating variable stars plays a very important role in stellar evolution under- standing. The Hertzsprung-Russell diagram is a powerful tool to track which stage of stellar life is represented by a particular type of variable stars. Let's see what major pulsating variable star types are and learn about their place on the H-R diagram. This approach is very useful, as it also allows to make a decision about a variability type of a star for which the properties are known partially. The Hertzsprung-Russell diagram shows a group of stars in different stages of their evolution. It is a plot showing a relationship between luminosity (or abso- lute magnitude) and stars' surface temperature (or spectral type). The bottom scale is ranging from high-temperature blue-white stars (left side of the diagram) to low-temperature red stars (right side). The position of a star on the diagram provides information about its present stage and its mass. Stars that burn hydrogen into helium lie on the diagonal branch, the so-called main sequence. In this article intrinsically pulsating variables are covered, showing their place on the H-R diagram. Pulsating variable stars form a broad and diverse class of objects showing the changes in brightness over a wide range of periods and magnitudes. Pulsations are generally split into two types: radial and non-radial. Radial pulsations mean the entire star expands and shrinks as a whole, while non- radial ones correspond to expanding of one part of a star and shrinking the other. Since the H-R diagram represents the color-luminosity relation, it is fairly easy to identify not only the effective temperature Intrinsic variable types on the Hertzsprung–Russell and absolute magnitude of stars, but the evolutionary diagram. -
198 6Apj. . .309. .7 32J the Astrophysical Journal, 309:732-736
32J .7 The Astrophysical Journal, 309:732-736,1986 October 15 kf 1986. The American Astronomical Society. All rights reserved. Printed in U.S.A. .309. 6ApJ. 198 RV TAURI STARS AS POST-ASYMPTOTIG GIANT BRANCH OBJECTS M.Jura Department of Astronomy, University of California, Los Angeles Received 1986 February 5 ; accepted 1986 April 8 ABSTRACT RV Tau stars are rare, luminous pulsators of spectral types F, G, and K. Analysis of the IRAS data shows that the mass-loss rates from RV Tau stars have apparently significantly decreased during the past ~500 yr -5 -1 from about 10 M0 yr , depending upon the metallicity of the stars and the grain emissivity at 60 /mi. It seems likely that these stars have just evolved from the phase of rapid mass loss, characteristic of the last stages of the asymptotic giant branch (AGB). The birthrate of RV Tau stars in the solar neighborhood is very roughly 6 x 10"4 kpc-3 yr-1, about a tenth of the birthrate of all planetary nebulae, and this is consistent with the view that we are witnessing the subset of stars undergoing post-AGB evolution that are low mass and at least in some cases of low metallicity. Most RV Tau stars will probably become planetary nebulae; others, however, may evolve sufficiently slowly that their envelopes will dissipate before being photoionized. Subject headings: infrared: sources — stars: evolution — stars: mass loss — stars: RV Tauri — stars : stellar statistics I. INTRODUCTION and a small bolometric correction, then, from equation (1), 3 The evolution of stars from the asymptotic giant branch again, L ~ 10 L0. -
Variable Stars
VARIABLE STARS RONALD E. MICKLE Denver, Colorado 80211 ©2001 Ronald E. Mickle ABSTRACT The objective of this paper is to research the causes for variability and identify selected stars within telescope reach. In addition, individual observations of the magnitudes (Mv) of selected variable stars were made and a plan designed for more extensive work on variable stars was developed. Variable stars are stars that vary in brightness. They can range from a thousandth of a magnitude to as much as 20 magnitudes. This range of magnitudes, referred to as amplitude variation, can have periods of variability ranging from a fraction of a second to years. Algol, one of the oldest know variables, was known to ancient astronomers to vary in brightness. Today over 30,000 variable stars are known and catalogued, and thousands more are suspected. Variable stars change their brightness for several reasons. Pulsating variables swell and shrink due to internal forces, while an eclipsing binary will dim when it is eclipsed by its binary companion. (Universe 1999; The Astrophysical Journal) Today measurements of the magnitudes of variable stars are made through visual observations using the naked eye, or instruments such as a charge- coupled device (CCD). The observations made for this paper were reported to the American Association of Variable Star Observers (AAVSO) via their website. The AAVSO website lists variable star organizations in 17 countries to which observations can be reported (AAVSO). 1. IDENTIFICATION OF STAR FIELDS Observations were made from Denver, Colorado, United States. Latitude and longitude coordinates are 40ºN, 105ºW. 1.1. EYEPIECE FIELD-OF-VIEW (FOV) AAVSO charts aid in locating the target variable. -
Variabelbulletinen Nr. 1
Variabelbulletinen Nr 1 Augusti 2012 54600 54800 55000 55200 55400 55600 55800 56000 56200 3 4 5 6 7 8 9 10 11 12 13 14 Ljuskurva för miran Chi Cygni 2 Variabelbulletinen Nr 1. Augusti 2012. ISSN 2001-3930 En publikation från Svensk AmatörAstronomisk Förening Variabelsektionen (SAAF/V) Sektionsledare Chris Allen Ansvariga för databasen SVO Thomas Karlsson och Robert Wahlström Redaktör Hans Bengtsson Icke signerat material har författats av redaktören. Innehållsförteckning Introduktion. …………………...…………………………………………………………………….……………………….…… 4 Hans Bengtsson: Klassiska miror och legendariska variabilister. ………………...…….…..... 4 Thomas Karlsson: Epsilon Aurigae. ….……………………...……………………………...………………..…. 16 Hans Bengtsson: Våra variabler. Första delen. ………………………………………..…….....….……. 16 Thomas Karlsson: Ljusstark supernova i M101. ………………………………………………..…….… 26 Gustav Holmberg: Några RCB-stjärnor säsongen 2011-2012. …....…………...……….……. 28 Thomas Karlsson: Bestämning av period för 58 variabler. …………..……………...……….…... 31 Thomas Karlsson: Maxima för miror. ………………………………………………………………...……….… 33 Thomas Karlsson: Fotometri i Sagitta och Vulpecula. …………………………………………….… 34 Statistisk från SVO. ……………..…………………………………………...………………………………………...…… 38 Hans Bengtsson: Variabelmöten – en ny tradition. …………...……………………………………….. 39 Hans Bengtsson: Flera flugor i samma smäll. …………………………...............................…………... 40 Förstasidan Ljuskurva för miran Chi Cygni. Följande observatörer har bidragit till diagrammet: Chris Allen (45), Hans Bengtsson (102), Göran Fredriksson (9),