PAGE i American Association of Variable Star Observers AAVSO U GEMINORUM LIGHT CURVES 1855 - 1985 * * * AAVSO MONOGRAPH 2 This monograph is dedicated to Margaret and Newton Mayall in recognition of their long-standing support of the Association and their distinguished contributions to Astronomy. Prepared by Janet A. Mattei Michael Saladyga Elizabeth O. Waagen Charles M. Jones Funds for preparation and publication provided by Margaret W. and R. Newton Mayall Clinton B. Ford Additional funds provided by ational Aeronautics and Space Administration (NASA) International Astronomical Union (IAU) AAVSO Members PAGE ii COPYRIGHT 1987 by the American Association of Variable Star Observers 25 Birch Street Cambridge, Massachusetts 02138 USA 373 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 Foreword v Observers of U Geminorum viii Information on U Geminorum x Key to Symbols x Historical Light Curve of U Geminorum, 1855 - 1964 1 Light Curves of U Geminorum, 1963 - 1985 3 iii PAGE iv is blank PAGE v U GEMINORUM LIGHT CURVES, 1855 - 1985 Introduction AAVSO long-term light curves on variable stars contain crucial information that has a significant bearing on many outstanding questions in astrophysics. With cataclysmic variables, these questions include stellar instability, time-varying processes in stars (recurrence time, duration, rise and decay times, unusual changes in the pattern of events), the structure of the complex binary, accreting white dwarfs (low luminosity x-ray sources), the dynamics of accretion in the degenerate star, the physics of accretion disks, and the problem of viscosity. In addition, the long-term light curves contain invaluable information on dwarf nova outbursts, the nature and origin of which are still not well understood. The long-term records of AAVSO will provide the basic set of observations which models of outburst phenomena in accretion disk systems must match. Long-term data published in the AAVSO Monograph series may help to answer some of the above questions. The mongraph format will enable us to present the long-term behavior of these stars, with each monograph containing 20 or more years' data on one star. We have begun this monograph series with cataclysmic variables because of the high demand for data on these stars, and also because no AAVSO data on them from 1963 to the present have been published. We will later proceed with the publication of other types of stars. U Geminorum Light Curves, 1855 - 1985 AAVSO Monograph 2 contains light curves of U Geminorum from its dicovery by the English astronoier J. R. Hind on December 15, 1855, to December 1, 1964. The AAVSO historical light curve from December 15, 1855 to December 1, 1964 (J.D. 2398933 - 2438731) is presented on pages 1 and 2. These light curves have been included to give a more complete picture of U Geminorum's behavior. The observations that comprise these light curves have been published in Harvard Annals, Volume 55, (1855 - 1907); 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 (1961 - 1963). Pages 3 through 42 contain light curves from 1963 to 1985, with each dot representing one observation. Pertinent information on U Geminorum and a key to symbols in the light curves are given on page x. A scaled grid is provided with the monograph to assist in determining the exact date and magnitude of any data point. Data are plotted Julian date versus visual magnitude, and the start of each year (Jan 0) is indicated along the upper axis. The observations in this monograph are the contributions of AAVSO members or observers in the United States and abroad. 358 observers have contributed over 14,000 observations to these light curves. The names and v PAGE vi observer codes of observers who have contributed observations to this monograph are given on pages viii and ix. In preparing the data for publication, each observation was checked for accuracy, first using a specifically generated computer program, then once again by my technical assistants Michael Saladyga and Elizabeth O. Waagen, and finally by me. The individual observations from 1963 to 1985 included in this monograph have been preserved on magnetic tape and printout. Copies of the magnetic tape or a listing of observations for further in-depth study may be obtained by writing to the AAVSO Director. The observations before 1960 are not in machine readable form at this time. However, we are in the process of making these observations also machine-readable. Acknowledgements We dedicate this monograph to Margaret and Newton Mayall. During her Directorship of the AAVSO from 1949 to 1974, Margaret compiled, organized, and published observations of U Geminorum. Together with Newton, they prepared the historical light curve found here on pages 1 and 2. Margaret and Newton have contributed generously to the preparation of this monograph. We extend our very sincere thanks to them. Our special thanks go to Clinton B. Ford for his very generous contribution for the preparation of this and subsequent monographs. We acknowledge with thanks the support provided through the National Aeronautics and Space Administration (NASA) HEAO-2 Guest Investigator Program (Grant NAG8-544) for the preparation of this and following monographs. Our special thanks to 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. Our sincere thanks go to AAVSO members and friends for their contributions to prepare these monographs. We gratefully acknowledge the support provided through National Science Foundation Grant AST 7910576 for computerization of a portion of the data in this monograph. We acknowledge with thanks the computer support of the Harvard- Smithsonian Center for Astrophysics and the continued support of Professor Owen J. Gingerich and Miss Barbara L. Welther. The checking of the data and the plotting of the light curves were accomplished using the computers at AAVSO Headquarters. We are indebted to vi PAGE vii the Research Corporation for the Charles H. Townes Fund Grant to the AAVSO to purchase the in-house computers without which we could not prepare the monographs. Many AAVSO assistants helped in the preparation of the data for publication. Special thanks go to Michael Saladyga for his careful checking of the data and for plotting the light curves, to Elizabeth O. Waagen for extracting the observations from our data files containing 3,500,000 observations and for her meticulous checking of the observations, and to Charles M. Jones, AAVSO's Margaret Mayall Assistant, for developing the computer programs to check the data. Peter M. Garnavich, Robert S. Hill, Karen J. Meech, Shelly K. Pope, and Richard J. Strazdas assisted in the development of the programs to manage the large volumes of data. Barbara Silva, Bethune Kelly, and many Harvard University and Massachusetts Institute of Technology student-assistants helped in making the data machine-readable. The dedication, the many, many hours of observing, and the untiring efforts of our observers 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 1987 vii PAGE viii OBSERVERS OF U GEMINORUM ADAMS, ROBERT M. AD CRUMRINE, ROBERT CRR AKIYOSHI, TARO C. AYT CUNNINGHAM, DOUG CUN ALBRECHT, WILLIAM B. AB CURTIS, GEORGE, JR. CSH ALDERING, GREGORY S. ALS DANSKIN, KEITH H. DAK ANDERSEN, ODD'IVAR AOD DARVANN, TRON A. DTA ANDERSON, CURTIS E. AC DAVIDSON, GREG DV ANDRESS, J. ROBERT AJR DAVIS, JACK DAJ ANNAL, ROBERT J. ANN DE MARTINO, ROBERT DEA ARIAIL, ROBERT B. ARI DE YOUNG, JAMES A. DEY ARNOLD, LUC ARN DEBOOSERE, FRANK DBF AUBAD, J. AUB DECEUNINCK, STEFAAN DES BAKER, TIM R. BTR DICKINSON, R. T. DT BALDWIN, MARVIN E. BM DIERICK, DOMINIQUE DMN BANKS, JAMES BJ DIETHELM, ROGER DRG BARKSDALE, WILLIAM BWK DIXON, ROBERT DRX BARNHART, STEPHEN F. BSF DOMBROWSKI, PHILIP DPL BARONI, SANDRO BSR DOMENY, GABOR (ALSO DOM) GDB BAUER, JOHANN BAU DUCOTY, RICHARD DRY BECKMAN, KENNETH BKK DURUY, M. V. DUR BENNER, TERRY BTY DYCK, GERALD DGP BERGER, L. BEG ECKENDORF, JAMES H. ECJ BERNSTROM, MARVIN BML ECKERT, CHRISTOPH ECK BILODEAU, GERALD A. BIL EHRHART, EDWARD EHR BLAGG, BILL BGB EMERSON, GARY P. EM BOHME, DIETMAR BOH ENSIGN, ROY K. ERK BOHN, DENNIS BOD ERIKSSON, SOREN EKS BOIS, BERNARD BOI FARRAR, W. B., JR. FRW BORDNER, CHARLES BNC FAUSEL, CHARLES A. FCA BORNHURST, LARRY BOR FEIJTH, HENDRIK FJH BORTLE, JOHN E. BRJ FERNALD, CYRUS F. FE BORZELLI, CARMINE BZC FETTERMAN, THOMAS I. FET BOUMA, R. J. BMU FLEET, RICHARD W. FLT BRADLEY, PHILIP A. BAP FLYNN, EDWARD M. FEM BRETL, THOMAS C. BTB FORCZYK, STEPHEN FZS BREWSTER, MICHAEL R. BMI FORD, CLINTON B. FD BRIL, HENK BHN FORTIER, GEORGE L. FT BRIN, DANIEL BDN FRIGON, LEON A. FRI BRIN, DAVID BDV FRITON, EDWIN E. FR BRITISH AST. ASSOC. BAA FULLER, DALE B. FLR BROOKS, JAMES E. BRK GARNAVICH, PETER GAP BROWN, BARRY BRB GARSZTKA, J. P. GAZ BRYDEN, ROBERT BYD GAYDOS, MARK GAY BUHROW, RUSS BUW GLENN, FLORENCE GLF CALDER, JOHN B. CDE GLENN, WILLIAM H. GLW CAMPNEY, WALTER CWA GOFF, BILL GFB CAMPONOVO, AMBROSIO CPA GONDOLA, ANTHONY E. GDA CANDELA, JOSEPH CEA GOODWIN, PAUL N. GOP CARDONA, CHARLES CCD GRANSLO, BJORN H. GRL CARPENTER, CLAUDE B. CE GRIESE, JOHN W. III GRI CARTER, BRIAN A. CTB GRZELCZYK, HEINZ GRZ CAVAGNA, MARCO CIT GUNTHER, J. GUN CHAPLE, GLENN, JR. CGF HAGLUND, MICHAEL E. HAG CHEW, ROBERT L. CHW HALBACH, EDWARD A. HK CHILDRESS, R. KEN CRK HANNON JAMES HAN CHOATE, ROBERT CHR HANSON, GENE HSG CLANCY, SEAN CLL HARRINGTON, PHILIP HRR CLARK, WAYNE CLK HARTMANN, FERDINAND H COCHRAN, HARRY F. CCR HAWLEY, WALTER HWL COLIN, JOSEPH COI HAYDEN, EDWARD R. HAY COLLINS, PETER L. COL HAZEL, LAWRENCE HZL COMELLO, G. CMG HEIFNER, MARK A. HEF CONNORS, MARTIN G. CNS HEISER, ERWIN HEE CONSTANZO, DANIEL CSD HEYNDRICKX, BRUNO HEY COOK, LEWIS M. COO HIETT, LANCASTER HE COOK, STEPHEN P. CK HILL, RICHARD E. HRI CRAGG, THOMAS A. CR HIRASAWA, YASUO HIR HONDA, HIDEO HOH HOOGEVEEN, GEERT HOO HOPP, ULRICH HOP HORTON, IDA HTI HOSSFIELD, CASPER H. HSF HOUGH, DAVID HOU HOUSTON, WALTER S. HU HUBBARD, RT. REV. R. HUB HUGHES, HARRY, JR. HUH HUGHES, DONNA J. HUO HURLESS, CAROLYN HR IDEM, MICHAEL IML ITO, MASAYUKI ITO JACOBS, TOM JCT JAMES, ROBERT A. JM JEFFREY, J. THOMAS JJT JOHNSON, GUS E. JOG JONES, M. V. JMV JONES, MICHAEL I. JNM JONES, ROBERT JOR KANE, PHILLIP KPS KELLEY, GEORGE, W. KLY KELLY, KEN KEK KIEHL, MATTHIAS KIM KING, ROBERT P. KRB KIRBY, PHILLIP E. KIR KIRBY-SMITH, H. T. KBS KLEBERT, KLAUS KLK KLINTING, OLE KON KNIGHT, STEPHEN P. KSP KNOX, OSWALD J. KOJ KOEHLER, KARL F. KKF KOHL, GOERGE KLG KOLMAN, ROGER S. KRS KRISCH, GUNTHER KIS KRISCIUNAS, KEVIN L. KRK KRUTA, JAROSLAV KRU KUHNS, JAMES L. KUH KUIPERS, GAUKE KPG KUWABARA, TAKEHISA KUW LACASSIN, GILBERT LGT LACY, CLAUD LC LACY, H. J. LCH LANGHANS, THOMAS W. LTW LAURENT, BERGER LAB LENSS, IVARS LNS LEVESQUE, ADRIAN J. LAJ LEVY, DAVID H. LVY LINDBLOOM, GEORGE G. LNB LOCHER, KURT LK LORING, DANIEL P. LRD LOVETT, JAMES LVT LOWDER, WAYNE M. LX LOWRY, WILLIAM I. LW LUCAS, MRS. JAMES LS LUDWIG, CLUYSE LCS LUKAS, RAINER Z. LKS LUTZ, JON H. LTJ LYNCH, RICHARD F. LYR MAAG, RUSSEL C. MAA MADDEN, PATRICK J. MDD MARCARIO, MIKE MCO MARISKA, JOHN MRJ MATEO, MARIO MTO MATTEI, MICHAEL MTM MAYER, ERNST H. MYR viii PAGE ix MAYER, ERNST W., JR. MYW POWELL, EUGENE A. PO MC CALLUM, ROBERT MCB PRICE, LELAND H. PRI MC GINNS, GARY MGG QUADT, PETER H. QD MC GWIER, ROBERT MGT RAWSTRON, G. O. RW MC INNERNY, BRIAN J. MCI RAYNOR, LYNN O. RNR MC KENNA, JEROME MKJ REAVES, RICHARD E. RRE MC KEOWN, KEVIN M. MKK REINHART, CHARLES C. RNT MC MILLAN, BETTY MBC RENNER, CARL J. RCJ MEDWAY, KENNETH J. MED RENNER, THOMAS RNN MEGGINSON, D. (ALSO M30) MDG RICKER, CHARLES L. RQ MENDELL, PAUL MLP RIGGS, JOHN L. RJI MEZOSI, CSABA MEZ ROCHE, HYMAN RHY MICHAELS, EDWARD MHL RONEY, J. MICHAEL ROJ MIDTSKOGEN, MOK ROSEBRUGH, DAVID W. RB MILTON, RUSSELL MTL ROSS, GARY M. ROG MINOIS, J. MIS ROYER, RONALD RR MINTER, TODD MTD SABIA, JOHN D. SJD MITSCHKE, FEDOR MIT SABINE, KENNETH M. SAB MIZSER, ATTILA MZS SAKARIAS, MICHAEL SKM MOCHIZUKI, ETSUIKU MCE SAKUMA, SEI-ICHI SSU MOGELINSKI, JERRY MGJ SALADZIUS, ROGER SZR MONELLA, RINALDO MAR SAMOLYK, GERRY SAH MONSKE, ROBERT L. MOR SANDEL, JEFF G. SNL MONTAGUE, ALLEN C. MJ SARRAFIAN, HARRISON SRH MONTAGUE, FREDERICK MF SATOSHI, AKITA ASK MOORE, PATRICK MOP SCANDINAVIAN AST. SELSK. SAS MORGAN, JAMES E. MOJ SCHAUPP, RICHARD W. SRW MORRIS, CHARLES S. MRR SCHMITZ, VICKI SV MORRISON, PATRICK D. MRO SCHROYENS, ANN SCY MUIRDEN, JAMES MRD SCHROYENS, DANIEL SDH MULLIGAN, F. KIRBY MFK SCHWEITZER, EMILE SCZ MURN, PAUL MUR SCOVIL, CHARLES E. SCE MURPHY, MIKE MUM SEALY, ROBERT N. SL NEDERLAN. VER. V.W. STER. NDR SHARPE, S. B. SHS NEMETH, BAKOS NTH SHARPLESS, ALBERT P. SSA NISHIMURA, KEN NIK SHEPPARD, ROBERT T. SRT NORDBY, JOHN M. NBY SIMMONS, NEIL A. SNE NORTON, THOMAS S. NTS SKINNER, C. R. SKN OBERSTATTER, ALPHONSE OF SKOTTEGARD, PETER N. SKT ORAVEC, EDWARD G. OV SMALL, BRUCE SLB OSORIO, JOSE RIPERO OJR SMITH, C. J. SMH O'MEARA, STEPHAN OME SMITH, HORACE A. SHA PADILLA, STEVE PAS SMITH, MICHAEL B. STL PATRICK, RAYMOND PRN SODER, JAMES SOD PEARCE, ERIC C. PCE SPRATT, CHRISTOPHER SC PELTIER, LESLIE C. P STANTON, RICHARD H. STR PEREZ, ALAIN PZA STECKNER, THOMAS K. SKS PETERSON, H. ALLEN PTA STEFFEY, PHILIP C. STI PETTENGILL, D. B. PED STEGMANN, PAUL SGP PEZZAROSSA, CARLO PEZ STEPHANOPOULOS, GEORGE STF PIKE, ROBERT PIK STEPHENS, ROBERT D. SDR PORTER, ALAIN POA STOKES, ARTHUR J. SAJ SUGARMAN, MICHAEL D. SGM SULLIVAN, CHARLES E. SUL SULLIVAN, THOMAS FR. ST SURAWSKI, URSULA E. J. SUR SVENTEK, PAUL SVN SWANBERG, ROBERT F. SB SZOKE, BALAZS SKB SZYBOWICZ, THEODORE SZY TABOADA R., DOMINGO TB TAVARES, OLIVEIROS C. TV THOMAS, HOWARD D. TM THOMAS, JAMES TJ THOMAS, RON P. TMR THOMPSON, MICHAEL E. TME THOMPSON, RAYMOND R. TPR TOONE, JOHN TOO TORRES, EDUARDO CIFUENTES TCE TROIANI, DANIEL M. TDM TROMMER, DIRK TRR VAN CAUTEREN, PAUL VCP VANIER, PIERRE VNL VEDRENNE, PAUL VED VERDENET, MICHEL VET VISOCKI, GARY VIS VLASIC, JOHN C. VJC VOLLMAN, WOLFGANG VOL VUYLSTEKE, PIETER VYP WARNER, BIAN D. WAB WASSON, NORMAN F. WNF WATERS, FLOYD H. WTF WEBB, WILLIAM V. WBB WEBER, RICHARD J. WER WEIER, DAVID D. WEI WELCH, DOUGLAS L. WEL WESOLOWSKI, MIKE WEM WEST, JOHN WTJ WHITEHEAD, JAMES M. WJ WIEROWSKI, RAYMOND E. WRE WILLIAMS, DAVID B. WI WILLIAMS, THOMAS R. WLM WILS, PATRICK WLP WILSON, THOMAS W. WSN WINGATE, BRUCE WNB WITTEN, BLAKE C. WTN WOLPERT, BOB WBT YOUNG, ROBERT R. YON ZALEZSAK, TAMAS ZLT ZANOTTA, MAURO ZAM ZELLER, PAUL A. ZPA ZIMMERMAN, DENNIS ZMM ZIT, RAY ZT CONTRIBUTING ASTRONOMICAL ORGANIZATIONS Association Francaise des Observateurs d'Etoiles Variables (France) Astronomical Society of Southern Africa, Variable Star Section Astronomischer Jugendclub (Austria) Berliner Arbeitsgemeinschaft fur Varanderliche Sterne (West Germany) British Astronomical Association, Variable Star Section (England)--(BAA) Japan Astronomical Study Association Nederlandse Vereniging voor Weeren Sterrenkunde, Werkgroep Veranderlijke Sterren (Netherlands)--(NDR) Norsk Astronomisk Selskap, Variable Stjernegruppen (Norway) Pleione Valtozocsillag-eszlelo Halozat (Hungary) Royal Astronomical Society of Canada Scandinavian Astronomisk Selskap--(SAS) Vereniging Voor Sterrenkunde, Werkgroep Vanderlijke Sterren (Belgium) ix PAGE x INFORMATION ON U GEMINORUM Right Ascension Declination Position: (1900) 07h 49m 10s +22o 15.9' (1950) 07 52 08 +22 08.1 (2000) 07 55 06 +22 00.2 Type: Cataclysmic variable - dwarf nova of U Geminorum type Average Outburst Frequency: 102 days Orbital Period: 0.176906 day (4h 14m 45s) Spectra (secondary): M4.5V Mass Ratio (primary/secondary): 2.09 +/- 0.15 Mass (primary): 1.18 Mo +/- 0.15 Mass (secondary): 0.56 Mo +/- 0.06 Orbital Inclination: 67 degrees +/- 8 Other Information: - Occurrence of transient oscillations of low coherency - Occurrence of eclipses (1 eclipse per orbital revolution) - Double-line spectroscopic binary - x-ray source (hard and soft x-ray) 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). x PAGE xi U GEMINORUM LIGHT CURVES 1855 - 1985