PAGE i R Y S A G I T T A R I I L I G H T C U R V E S 1 8 9 2 - 1 9 9 0 AAVSO MONOGRAPH 5 This monograph is dedicated to Dorrit Hoffleit in recognition of her devoted service and many contributions to the Association and to variable star astronomy. Prepared by Janet A. Mattei Elizabeth O. Waagen E. Grant Foster Funds for preparation and publication provided by Dorrit Hoffleit Clinton B. Ford Additional funds provided by AAVSO Members International Astronomical Union (IAU) PAGE ii ISBN 1-878174-04-5 COPYRIGHT 1994 by the American Association of Variable Star Observers 25 Birch Street Cambridge, Massachusetts 02138 USA All rights reserved. All commercial use of any part of this book requires the written permission of the AAVSO. All non-commercial use by individuals and educators is granted without restriction. PAGE iii TABLE OF CONTENTS Introduction v Observers of RY Sagittarii vii Information on RY Sagittarii ix Key to Symbols ix Historical Light Curve of RY Sagittarii, 1892 - 1972 1 Computer-Generated Light Curves of RY Sagittarii, 1963 - 1990 2 PAGE iv is blank PAGE v RY SAGITTARII LIGHT CURVES, 1892 - 1990 Introduction AAVSO long-term light curves of variable stars contain crucial information that has a significant bearing on many outstanding questions in astrophysics. These light curves define the long-term behavior of variable stars and provide the basic set of observations that may be used to correlate multiwavelength data, to test theories, and match models. The monograph format enables us to present long-term variable star observations, with each Monograph containing 20 or more years of computer- generated light curves on one star. RY Sagittarii Light Curves, 1892 - 1990 The variability of RY Sagittarii was first suspected by Colonel E. E. Markwick of Gibraltar during his comparison of the Uranometria Argentina with the sky. He reported it to Edward C. Pickering, Director of Harvard College Observatory, as a 7th magnitude star in July 1893, and then fainter than 9 on 12 September 1893. Its variability was spectroscopically confirmed by Williamina Fleming and the information published in Harvard Observatory Circular, No. 7, by Edward C. Pickering on 5 June 1896. AAVSO Monograph 5 contains light curves of RY Sagittarii from 1892 through 1990. The light curve on page 1 is the AAVSO historical mean light curve of RY Sagittarii from 1892 to 1972. It has been included to give more complete information on the long-term behavior of RY Sagittarii. The early part of the historical light curve was compiled by Leon Campbell, first Recorder of AAVSO, from visual and photographic observations. Most of the observations after 1911 were made by members of the AAVSO. The later part of the historical light curve was compiled and the light curve of page 1 prepared and published by Margaret W. Mayall, the second Recorder and Director Emeritus of the AAVSO, in Journ. Royal Astron. Soc. Canada, Volume 66, 233, 1972. The AAVSO observations that comprise this historical light curve have been published in Popular Astronomy, Volumes 19 - 43 (1917 - 1935); Harvard Annals, Volumes 104 - 107 and 110 - 116 (1935 - 1946); AAVSO Quarterly Reports 1 - 27 (1946 - 1961); and AAVSO Report 29. Pages 2 through 12 contain computer-generated light curves from 1963 through 1990, with each dot representing one observation. Observations are plotted Julian date versus magnitude, and the start of each year (January 0) is indicated along the upper axis. A scaled grid is provided to assist in determining the exact date and magnitude of each observation. The observations that make up these light curves are the contributions of AAVSO members or observers in the United States and abroad. 261 observers have contributed 10,147 observations to the computer-generated light curves. The observer codes, names, and the number of observations made by each observer are listed on pages vii through viii. Factual information on RY Sagittarii and a Key to Symbols are given on page ix. In preparing the data for publication, each observation was evaluated for accuracy by my technical assistant Elizabeth O. Waagen, and by me. Computer programs used in evaluating and plotting the observations were developed by my technical assistant E. Grant Foster. The observations from 1963 through 1990 in this monograph have been preserved on magnetic tape, cartridge, and printout. Electronic, diskette, magnetic tape, or printout copies of observations for further analysis may be obtained by writing to the AAVSO Director. v PAGE vi Acknowledgements We dedicate AAVSO Monograph 5 to Dorrit Hoffleit, in recognition of her devoted service and invaluable contributions to variable star astronomy and the AAVSO. Dedicating this monograph on RY Sagittarii to Dorrit is particularly special for us, since the constellation of Sagittarius has been of great interest to Dorrit for decades. It is one of the constellations on which she focused her attention and research during her 21 years of Directorship of the Maria Mitchell Observatory in Nantucket, Massachusetts. Dorrit and her over 100 summer students, mostly women, discovered many new variable stars in Sagittarius and determined their period and behavior. We remember Clinton B. Ford with special gratitude and thanks for his very generous contribution for the preparation of this and other monographs and monograph supplements. Our sincere thanks go to AAVSO members and friends for their contributions towards the preparation of these monographs and monograph supplements. We thank the International Astronomical Union (IAU) for their support of our monograph series and for the grant provided to the AAVSO to publish this and other monographs and monograph supplements. We gratefully acknowledge the support provided through National Science Foundation Grant AST 7910576 for computerization of a portion of the data in this monograph. The evaluation of the data and the preparation of this monograph were accomplished using the computer facilities at AAVSO Headquarters. We are indebted to the National Aeronautics and Space Administration (grant awards NAGW 1493 and NAG 5-1459), the Kenilworth Fund, and the Theodore H. Dunham Fund for Astrophysical Research for grants to purchase the computer hardware without which we could not have prepared this publication. We acknowledge with thanks the computer support of the Smithsonian Astrophysical Observatory and the continued support of Professor Owen J. Gingerich and Miss Barbara L. Welther. Many AAVSO assistants helped in the preparation of the data for publication. Special thanks go to Elizabeth O. Waagen for evaluating the observations, and to E. Grant Foster for developing the computer programs for the IBM-PC compatible MS-DOS computers at AAVSO headquarters to evaluate, plot, and prepare the data for publication, and for generating the computer light curves. My thanks go to Robert S. Hill, Charles M. Jones, and Richard J. Strazdas, who assisted in the early development of the programs to manage the large volumes of data using the Smithsonian Astrophysical Observatory computers, and to Barbara J. Silva, Douglas Van Orsow, Young Lim, Bethune Kelly, Michael Bickford, Maura Kennedy, and several other student-assistants who helped in making the observations computer-readable. The dedication, the many, many hours of observing, and the untiring efforts of our observers worldwide, in pursuit of contributing to variable star astronomy, have made this publication possible. Our very sincere thanks and gratitude go to them for their valuable astronomical contributions. Janet Akyuz Mattei Director Cambridge, Massachusetts January 1994 vi PAGE vii CONTRIBUTORS TO AAVSO DATA ON RY SAGITTARII 1963 - 1990 AYT T. Akiyoshi 2 GAJ J. Garcia 3 MEB E. Matteo 1 AB W. Albrecht 155 GCP C. Gerber 18 MYR E. Mayer 14 AAA A. Alves 15 GMJ M. Geyser 2 MCF T. McFarland 2 AJ J. Anderer 11 GJ J. Goehring 23 MKK K. McKeown 7 AC C. Anderson 13 GZL L. Gomez 1 MED K. Medway 9 ANN R. Annal 23 GOP P. Goodwin 10 MDG D. Megginson 65 ARI R. Ariail 76 GRC A. Granc 11 MHI H. Menali 4 AKT T. Atkin 6 GRI J. Griese 4 MZS A. Mizser 17 BM M. Baldwin 25 GDJ D. Griffith 1 MGJ J. Mogelinski 6 BJ J. Banks 6 GIA A. Grima 2 MOR R. Monske 66 BMA M. Barone 107 GUN J. Gunther 1 MO W. Moore 1 BAU J. Bauer 9 HK E. Halbach 36 MOJ J. Morgan 51 BBA B. Beaman 3 HMR R. Ham 14 MOI E. Morillon 7 BIC L. Bichon 6 HAV R. Harvan 53 MRR C. Morris 1 BLD D. Blane 103 HKP K. Haslag 1 MB A. Morrisby 73 BAX A. Boattini 2 HZL L. Hazel 7 MOW W. Morrison 196 BOJ J. Bodenstein 1 HEN C. Henshaw 101 MUR P. Murn 6 BOR L. Bornhurst 1 HJN J. Hers 22 MSU S. Murphy 7 BRJ J. Bortle 60 HEV Z. Hevesi 1 MZJ J. Muzzio 2 BZC C. Borzelli 1 HE L. Hiett 480 BAO A. Nemeth-Buhin 1 BRG B. Bourgeois 3 HSN N. Higgs 103 NM M. Newberry 3 BAP P. Bradley 4 HRI R. E. Hill 5 NTS T. Norton 4 BDT D. Branchett 53 HIL R. L. Hill 2 NVK M. Novak 26 BSM S. Brincat 52 HGM M. Hogan 1 NOG G. Nowak 7 BLP P. Brlas 9 HTI I. Horton 1 OER E. Ofek 1 BNK N. Brown 3 HSF C. Hossfield 38 OME S. O'Meara 1 BUO A. Bueno 25 HOU D. Hough 1 OV E. Oravec 9 BJU J. Buss 36 HR C. Hurless 339 OJR J. Osorio 1 CBA R. Cabrera 11 IML M. Idem 1 OB D. Overbeek 1430 CWA W. Campney 15 ING S. Ingate 3 PLA A. Padilla Filho 10 CPA A. Camponovo 60 ITO M. Ito 30 PAO S. Paolantonio 11 CJA J. Campos 186 IFJ F. Ives 12 PLZ L. Pazzi 36 CE C. Carpenter 1 JKM M. Jackson 57 PTI N. Peattie 6 CAS B. Casseres 1 JM R. James 1 P L. Peltier 398 CMA M. Cerruti 44 JEN C. Jenkins 18 PAE A. Pereira 54 CCN R. Chacon 13 JOG G. Johnson 26 PFK F. Pesci 1 CST G. Christensen 5 JKL K. Jones 4 POD D. Pestana Galvan 14 CLL S. Clancy 1 JMV M. I. Jones 3 PED D. Pettengill 16 CWP W. Clarke 13 JNM M. V. Jones 1 PFA J. Pfannerstill 1 COL P. Collins 298 KLY G. Kelley 10 PIJ J. Piriti 3 CD D. Conger 11 KEK K. Kelly 5 PO E. Powell 48 COO L. Cook 2 KSZ S. Keszthely 3 PRG G. Prosser 20 COK R. Cook 6 KIR R. Kilby 5 RNT C. Reinhart 1 COM T. Cooper 122 KRB R. King 4 RCJ C. Renner 5 CR T. Cragg 204 KGT G. Knight 2 RNN T. Renner 1 DSL L. Dasilva 1 KSP S. Knight 1 RJI J. Riggs 7 DV G. Davidson 1 KHL M. Kohl 2 RMA M. Rodrigues 2 DWN D. Dawson 1 KHJ H. Koller 8 RDJ J. Roediger 4 DCC C. DeCarhalvo 2 KRS R. Kolman 5 RB D. Rosebrugh 127 DK R. DeKock 337 KMA M. Komorous 112 RND D. Rosenfield 5 DVR R. de la Vega 9 KOP M. Kopinsky 5 RLU L. Rossi 2 DEY J. DeYoung 16 KOS A. Kosa-Kiss 3 RR R. Royer 42 GDB G. Domeny 4 KOA M. Koshiro 32 RJF J. Ruhl 83 DZS S. Dominguez 64 KVI I. Kovacs 3 RPJ P. Ryan 9 DWR W. Douglas 1 KUH J. Kuhns 15 SAB K. Sabine 31 DAG A. Dredge 27 KBO R. Kuplin 2 SCD D. Saccone 2 DRR R. Dudley 3 LCH H. Lacy 2 SKM M. Sakarias 6 DDR O. Dunai 3 LPR R. LaPerna 2 SSU S. Sakuma 1 DKF M. Durkefalden 1 LMF M. Lara 24 SZR R. Saladzius 2 ELD D. Elias 1 LKG K. Larson 1 STC G. Santacana 1 ELW S. Elwin 2 LWS M. Lawson 5 SVT T. Saville 1 EWK K. Ewing 2 LZT T. Lazuka 101 SCK B. Schaefer 1 FE C. Fernald 151 LVY D. Levy 5 SIR P. Schiller 1 FRF R. Fidrich 6 LEF F. Ley 2 SPK P. Schmeer 1 FIR R. Field 12 LIM R. Lima 10 SV V. Schmitz 2 FLT R. Fleet 129 LK K. Locher 6 SMJ J. Scholl 41 FFC F. Foldesi 4 LVT J. Lovett 6 SCX E. Sciaroni 2 FD C. Ford 16 LX W. Lowder 20 SCE C. Scovil 7 FBN B. Fraser 4 MAN C. Mahnkey 2 SS C. Segers 7 FJX J. Fraser 1 MCO M. Marcario 5 SEZ J. Segonzat 3 FSR R. Fraser 6 MHG H. Marraco 35 SHS S. Sharpe 79 FAA A. Frosina 3 MAF G. Marshall 1 SSA A. Sharpless 1 vii PAGE viii CONTRIBUTORS TO AAVSO DATA ON RY SAGITTARII (cont'd) 1963 - 1990 SHQ O. Shemmer 1 TJ J. Thomas 17 VLJ J. Volhard 2 SLH L. Shotter 5 TMR R. Thomas 15 WLL H. Walls 3 SKL K. Simmons 5 TME M. Thompson 14 WSM S. Walsh 83 SKT P. Skottegard 4 THR R. Thompson 1 WTF F. Waters 1 SMD D. Smith 1 THS S. Thompson 56 WRG R. Watson 25 STR R. Stanton 1 TRJ R. Thomson 10 WER R. Weber 54 STF G. Stefanopoulos 159 THU B. Thouet 128 WLP P. Wils 1 STI P. Steffey 141 TOO J. Toone 3 WSN T. Wilson 80 SWT R. Stewart 1 TFN F. Traynor 7 WTN B. Witten 4 SDT D. Strydom 9 TUC C. Turk 30 WCL C. Womack 32 SUS D. Sussmann 16 TNL N. Turner 23 WUN E. Wunder 1 SVN P. Sventek 39 VAM M. Vattuone 598 ZAF J. Zaffi 7 TB D. Taboada 1 VED P. Vedrenne 75 ZLT T. Zalezsak 3 TZR R. Tanzer 2 VET M. Verdenet 80 ZAM M. Zanotta 2 TDB D. Taylor 1 VIN J. Vincent 800 ZT R. Zit 2 CONTRIBUTING ASTRONOMICAL ORGANIZATIONS Asociacion Argentina Amigos de la Astronomia Association Francaise des Observateurs d'Etoiles Variables (France) Astronomical Society of Southern Africa, Variable Star Section Astronomischer Jugendclub (Austria) Astronomisk Selskab (Scandinavia) British Astronomical Association, Variable Star Section (England) British Astronomical Association of New South Wales (Australia) Bundesdeutsche Arbeitsgemeinschaft fur Veranderliche Sterne e.V.(BAV)(Germany) Liga Ibero-Americana de Astronomia (South America) Magyar Csillagaszati Egyesulet, Valtozocsillagok (Hungary) Nederlandse Vereniging Voor Weer-en Sterrenkunde, Werkgroep Veranderlijke Sterren (Netherlands) Norsk Astronomisk Selskap, Variable Stjernegruppen (Norway) Planetario e Observatorio Astronomico do Colegio Estadual do Parana (Brazil) Red de Observatores de Estrellas Variables - MIRA (Spain) Royal Astronomical Society of Canada Royal Astronomical Society of New Zealand, Variable Star Section Uniao Brasileira de Astronomia, Variable Star Commission (Brazil) Variable Star Observers League in Japan Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) viii PAGE ix INFORMATION ON RY SAGITTARII Right Ascension Declination Position: (1900) 19h 10m 01s -33o 41.8' (1950) 19 13 17 -33 36.7 (2000) 19 16 33 -33 31.8 Type: R Coronae Borealis R Coronae Borealis stars are one of the rarest types of variable stars. High-luminosity stars of spectral type between B and R, they have carbon- and helium-rich and hydrogen-poor spectra, with emission lines of metals seen at minimum brightness. Optically,they are at maximum brightness most of the time, and at irregular intervals they show non-periodic fadings of 1 to 9 magnitudes, lasting from several tens to several hundreds of days. Small amplitude pulsations of several tenths of a magnitude in amplitude, with periods ranging from 20 to 100 days, are also seen in the light curves of some stars of this type. Spectrum: G0IAEP(C1,0) In the spectrum: G0 - spectrum type I - supergiant luminosity class A - hydrogen alpha Balmer line E - emission lines P - peculiar spectrum C1,0 - carbon star spectrum Other Information: In the optical light curve of RY Sagittarii, there are small amplitude light variations between 0.1 and 1.5 magnitudes and a 38.6-day period due to the pulsation of the star. KEY TO SYMBOLS Symbols used in this monograph are: . = 1 observation v = variable is fainter than the magnitude indicated by the vertex of the "v" on the light curve (variable not seen) ix PAGE x RY SAGITTARII LIGHT CURVES 1892 - 1990