PAGE i U G E M I N O R U M L I G H T C U R V E S 1 9 9 1 - 1 9 9 5 AAVSO MONOGRAPH 2 SUPPLEMENT 2 This monograph is dedicated to Richard A. and Josephine S. Danskin in recognition of their support of and contributions to the Association. Prepared by Janet A. Mattei Elizabeth O. Waagen E. Grant Foster Funds for preparation and publication provided by Richard A. and Josephine S. Danskin Clinton B. Ford Additional funds provided by AAVSO Members International Astronomical Union (IAU) ---------------------------------------------------------------------------- PAGE ii ISBN 1-878174-15-0 COPYRIGHT 1996 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 U Geminorum vii Information on U Geminorum ix Key to Symbols ix Light Curves of U Geminorum, 1991 - 1995 1 ----------------------------------------------------------------------------- PAGE iv is blank ----------------------------------------------------------------------------- PAGE v U GEMINORUM LIGHT CURVES, 1991 - 1995 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 behavior of variable stars and provide basic sets of observations for multiwavelength data correlation, data analysis, and for checking theories and matching models. The monograph format enables us to present long-term variable star behavior, with each Monograph containing 20 or more years of computer-generated light curves on one star. Each Supplement to a Monograph continues the light curves of the same star, bringing them more up-to-date. U Geminorum Light Curves, 1991 - 1995 AAVSO Monograph 2, Supplement 2, contains light curves of U Geminorum from 1991 through 1995 (JD 2448258 - 2450083). Pages 1 through 10 contain computer-generated light curves with each dot representing one observation. Observations are plotted Julian date versus magnitude, and the start of each year (January 1) is indicated along the upper axis. A scaled grid is provided to assist in determining the exact date and magnitude of any data point. Factual information on U Geminorum and a Key to Symbols are given on page ix. Earlier observations of U Geminorum have been published in AAVSO Monograph 2, U Geminorum Light Curves 1855 - 1985 and AAVSO Monograph 2, Supplement 1, U Geminorum Light Curves 1985 - 1990. The observations in AAVSO Monograph 2, Supplement 2, are the contributions of AAVSO members or observers in the United States and abroad. 221 observers have contributed 10,310 observations to these light curves. The names and observer codes of these observers are given on pages vii through viii. Organizations whose members have contributed observations to the AAVSO either individually or through their organization are listed on page viii. In preparing the data for publication, each observation was evaluated for accuracy by my senior technical assistant Elizabeth O. Waagen, and by me. Software used in evaluating and plotting the observations was developed by my technical assistant E. Grant Foster. The observations from 1991 through 1995 included in this monograph supplement have been preserved on compact disc, cartridge, and printout. Electronic, diskette, or printout copies of observations for further analysis may be obtained by writing or sending email to the AAVSO Director at aavso@aavso.org. The data may also be retrieved for personal use (not for publication or distribution) from the AAVSO's ftp site: ftp.aavso.org (198.116.78.2) in /pub/monographs, or its home page: http://www.aavso.org. Acknowledgements We dedicate AAVSO Monograph 2, Supplement 2, to Richard A. and Josephine S. Danskin, who have contributed generously towards the preparation of the AAVSO monographs and supplements. We extend our very sincere thanks to them. We remember with special thanks Clinton B. Ford for his very generous contribution for the preparation of this and subsequent monographs and monograph supplements. Our sincere thanks go to AAVSO members and friends for their contributions to v ---------------------------------------------------------------------------- PAGE vi prepare 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 acknowledge with thanks the computer support of the Smithsonian Astrophysical Observatory for preservation of the data. The evaluation of the data and the preparation of this monograph supplement were accomplished using the computer facilities at AAVSO Headquarters. This computer hardware was purchased through grants from 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. We gratefully acknowledge these grants. Many AAVSO assistants helped in the preparation of the data for publication. My special thanks go to Elizabeth O. Waagen for her careful evaluation of the observations and plotting the light curves, 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. Robert S. Hill, Charles M. Jones, and Richard J. Strazdas assisted in the initial development of the computer programs to manage the large volumes of data. Barbara Silva, Donna Eldridge, Douglas Van Orsow, Young Lim, Michael Bickford, and several other student-assistants have helped in making the data computer-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 April 1996 vi ----------------------------------------------------------------------------- PAGE vii CONTRIBUTORS TO AAVSO DATA ON U GEMINORUM 1991 - 1995 AAP ABBOTT, A. PATRICK 12 | HK HALBACH, EDWARD A. 2 | AMT ADAMS, MARK T. 93 | HAN HANNON, JAMES 2 | AB ALBRECHT, WILLIAM 186 | HAV HARVAN, RICHARD P. 36 | ALN ALLISON, RUDIE J. 2 | HAB HAYS JR., ROBERT H. 23 | BWY BAILEY, WAYNE 4 | HZL HAZEL, LAWRENCE 3 | BSR BARONI, SANDRO 2 | HEF HEIFNER, MARK A. 6 | BXR BARRY, RON 3 | HE HIETT, F. LANCASTER 30 | BBA BEAMAN, BARRY B. 2 | HIR HIRASAWA, YASUO 14 | BVD BEARD, DAVID J. 2 | HWD HODGSON, WILLIAM D. 8 | BTY BENNER, TERRY 15 | HJO HOLTROP, J. 6 | BEB BERG, RAYMOND 3 | HRB HORNBY, PETER W. 3 | BPM BERGE, PIERRE 1 | HPD HOULAHAN, PADRAIC 3 | BMM BIESMANS, MARC 2 | HUT HUNTER, TIMOTHY 4 | BQR BLAKE, ROGER A. 1 | IML IDEM, MICHAEL 87 | BAX BOATTINI, ANDREA 2 | JM JAMES, ROBERT A. 2 | BRJ BORTLE, JOHN E. 183 | JJS JANATA, JAROSLAV 2 | BMU BOUMA, R. J. 86 | JAJ JANSSENS, JAN 1 | BSM BRINCAT, STEPHEN M. 6 | JLT JENSEN, LASSE TEIST 83 | BOS BROENS, ERIC 34 | JRJ JOHANNS, R. J. 6 | BBT BROWNING, ROBERT R. 2 | JOG JOHNSON, GUS E. 1 | BOA BRUNO, ALAIN 8 | JON JONCKHEERE, KURT 3 | BTH BURROWS, THOMAS A. 33 | JSZ JOZSA, SANDOR 1 | CMP CAMPBELL, RICHARD 12 | KB KAMINSKI, WALTER J. 46 | CNT CHANTILES, DEAN 10 | KRB KING, ROBERT P. 149 | CGF CHAPLE JR., GLENN 3 | KBR KIRSHNER, BRIAN 2 | CIR CINTRON, ROBERT 3 | KIL KISS, LASZLO 18 | CLK CLARK, WAYNE E. 23 | KGT KNIGHT, GEORGE 1 | CNL COLE ARNAL, OSCAR 5 | KSP KNIGHT, STEPHEN P. 32 | COL COLLINS, PETER L. 50 | KHL KOHL, MICHAEL 24 | CMG COMELLO, GEORG 52 | KRS KOLMAN, ROGER S. 1 | CR CRAGG, THOMAS A. 69 | KMA KOMOROUS, MIROSLAV 19 | CCS CREIGH, CHARLES 3 | KOS KOSA-KISS, ATTILA 24 | CSM CSUKAS, MATYAS 6 | KKO KOSS, K. 1 | CCO CUBILLO, CARLOS F. 7 | KWO KRIEBEL, WOLFGANG 11 | DAH DAHLE, HAAKON 26 | KIS KRISCH, GUNTHER 9 | DMM DAMIANI, MATTEO 1 | KRK KRISCIUNAS, KEVIN 3 | DBR DECOTTIGNIES, BERNARD 4 | KPG KUIPERS, GAUKE 1 | DEA DEMARTINO, ROBERT 3 | LKG LARSON, KEVIN GARY 39 | DFR DEMPSEY, FRANCIS S. 1 | LZT LAZUKA, THOMAS 12 | DEK DEQUICK, KURT 1 | LNZ LENZ, GEORGE F. 2 | DTE DESLIJPERE, TOMMY 9 | LVT LOVETT, JAMES 13 | DJN DICKINSON, JON J. 3 | LBG LUBCKE, GILBERT C. 62 | DPA DIEPVENS, ALFONS 87 | LRE LUNSFORD, ROBERT 1 | DLA DILL, ALBERT G. 11 | LBB LUX, BARBARA A. 1 | DIL DILLON, WILLIAM G. 47 | MLI MAISLER, LEE 10 | DMY DOMBROWSKI, MARY 3 | MKN MAKIGUCHI, N. 1 | DPL DOMBROWSKI, PHILIP 46 | MJZ MANZORRO, JUAN 7 | DAB DUKES, ALBERT D. 2 | MRX MARX, HARALD 7 | DGP DYCK, GERALD P. 307 | MPR MAURER, PETER 9 | EWH EDWARDS, WILLIAM H. 3 | MGE MAVROFRIDIS, GEORGE 24 | EKG EKLUND, GARY 5 | MYR MAYER, ERNST H. 23 | ELD ELIAS, DEMETRIUS P. 4 | MKJ MCKENNA, JEROME F. 29 | EM EMERSON, GARY P. 1 | MIB MEDIAAS, IVAR B. 6 | FCA FAUSEL, CHARLES A. 6 | MED MEDWAY, KENNETH J. 32 | FJH FEIJTH, HENDRIK 221 | MOK MIDTSKOGEN, ORNULF 187 | FRF FIDRICH, ROBERT 27 | MRU MILLER, RICHARD F. 6 | FSE FOGLIA, SERGIO 1 | MZS MIZSER, ATTILA 23 | FFC FOLDESI, FERENC 8 | MRV MODIC, ROBERT J. 167 | GBZ GABZO, OFER 55 | MOX MOELLER, GERHARD 2 | GPA GARCIA, PACO 3 | MMI MOELLER, MICHAEL 36 | GJN GENSLER, JAN 8 | MOL MOLNAR JR., JAMES 17 | GGT GLENN, GARY 3 | MF MONTAGUE, FREDERICK 1 | GOP GOODWIN, PAUL N. 19 | MOJ MORGAN, JAMES E. 7 | GRL GRANSLO, BJOERN H. 35 | MOI MORILLON, ERIC 2 | GRI GRIESE III, JOHN W. 46 | MUY MUYLLAERT, EDDY 1 | GUB GUBBELS, GUIDO 5 | NRH NELSON, ROBERT 2 | GHD GUIDRY, HOWARD 1 | NBY NORDBY, JOHN M. 16 | GMM GUMLER, MICHAEL G. 6 | NVK NOVAK, MICHAEL 27 | GUN GUNTHER, JEAN 35 | OCN O'CONNOR, STEPHEN 2 | HTY HAGER, TIMOTHY 13 | ONJ O'NEILL, JOHN G. 8 | OES OESPER, DAVID 2 OER OFEK, ERAN 6 OJO OLESEN, J. OSTERGAARD 7 OJR OSORIO, JOSE RIPERO 54 PLA PADILLA FILHO, ANTONIO 5 PCC PAPINI, RICCARDO 1 PPS PAPP, SANDOR 75 PMA PARKER, MARK 2 PEI PEDERSEN, EIGIL 10 PMR PERALA, MARTTI R. 13 PTZ PIETZ, JOCHEN 15 PBE PIOLON, BENGT 4 POX POXON, MICHAEL 28 PYG POYNER, GARY 112 PCJ PREDOM, CHRISTOPHER 1 PUJ PUJOL, FRANCISCO 6 QPF QUINN, PETER F. 4 RAA RAASCH, RICHARD W. 3 RRB RAPHAEL, ROBERT B. 43 RJI RIGGS, JOHN I. 2 RPR ROBBINS, PHILLIP 72 RGL ROTEM, GILAD 21 RR ROYER, RONALD E. 96 SQV SAINZ, JAVIER 2 SJQ SAJTZ, ANDRAS 2 SSU SAKUMA, SEI-ICHI 26 SAH SAMOLYK, GERARD 3 SPQ SAPI, CSABA 4 SKI SARNECZKY, KRISTIAN 2 SPK SCHMEER, PATRICK 43 SCE SCOVIL, CHARLES E. 28 SHS SHARPE, STEVEN B. 31 SSA SHARPLESS, ALBERT 2 SHQ SHEMMER, OHAD 12 SIH SILHOL, MAX 5 SNE SIMMONS, NEIL A. 15 SC SPRATT, CHRISTOPHER 1 STR STANTON, RICHARD H. 10 STI STEFFEY, PHILIP C. 42 SPU STEPAN, PETR 1 SET STEPHAN, CHRISTOPHER 28 SWT STEWART, ROBERT J. 96 SUX SUAREZ, MAXIMO 2 SVN SVENTEK, PAUL L. 2 SSW SWIERCZYNSKI, STANISLAW 7 SDX SWORIN, DAVID J. 7 SBT SZABO, ROBERT 10 SKV SZARKA, LEVENTE 2 SNO SZENTASKO, LASZLO 135 TPI TASSIE, PIERRE 7 TDB TAYLOR, DANIEL 96 TPS TEPLICZKY, ISTVAN 3 THU THOUET, BERNARD 3 TMB TOMBELLI, MAURA 3 TRT TORDAI, TAMAS 1 TSC TRACY, SCOTT 17 TDM TROIANI, DANIEL M. 10 TSJ TSUJI, SEIJI 1 VBR VAN BEMMEL, HENRI 2 VCP VAN CAUTEREN, PAUL 46 VDE VAN DIJK, E. 1 VNL VAN LOO, F. R. 31 VDL VANDERLOOY, JOHAN 10 VDJ VANDIJK, J. F. H. 3 VHD VANHESSCHE, DIRK 4 VMT VANMUNSTER, TONNY 114 VED VEDRENNE, PAUL 35 VET VERDENET, MICHEL 174 VJF VIENS, JEAN-FRANCOIS 25 VGP VIGNIER, PHILLIPE 4 vii ----------------------------------------------------------------------------- PAGE viii CONTRIBUTORS TO AAVSO DATA ON U GEMINORUM (continued) 1991 - 1995 WEI WEIER, DAVID D. 8 | WJY WILMS, JOHNNY 1 | WEJ WEST, E. JAMES W. 7 | WLP WILS, PATRICK 1 | WDM WESTLUND, MARGARETA 2 | WDN WILSON, DANNY RAY 33 | WI WILLIAMS, DAVID B. 9 | WSN WILSON, THOMAS W. 22 | YRK YORK, DAVID O. 302 ZAG ZAJACZ, GYORGY 7 ZRE ZISSELL, RONALD E. 239 CONTRIBUTING ASTRONOMICAL ORGANIZATIONS Agrupacia Astronomica Albireo of Seville (Spain) 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) Grupo Astronomico Silos (Zaragoza, Spain) Grupo Canario de Estrellas Variables (Canary Islands, Spain) Israeli Astronomical Association, Variable Star Section Madrid Astronomical Association M1 (Spain) Liga Ibero-Americana de Astronomia (South America) Magyar Csillagaszati Egyesulet, Valtozocsillag Szakcsoport (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 Sociedad Astronomica 'Syrma' (Valladolid, Spain) Svensk Amator Astronomisk Forening, variabelsektionen (Sweden) Uniao Brasileira deAstronomia, Variable Star Commission (Brazil) Unione Astrofili Italiani (UAI) Variable Star Observers League in Japan Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) viii ---------------------------------------------------------------------------- PAGE ix INFORMATION ON U GEMINORUM Right Ascension Declination Position: (1900) 07h 49m 10s +22 degrees 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 (04:14:45) Spectrum (secondary): M4.5V Mass Ratio (primary/secondary): 2.09 +/- 0.15 Mass (primary): 1.18 solar masses +/- 0.15 Mass(secondary): 0.56 solar mass +/- 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 visual observation v = variable is fainter than the magnitude indicated by the vertex of the "v" on the light curve (variable not seen) Please note that there may appear to be horizontal lines in some parts of the light curves. These horizontal "lines" are in fact very dense concentrations of individual observations. There are also some clusters of observations that appear as vertical lines on the light curves. These vertical "lines" are observations made using CCD and have magnitudes reported to two or three decimal places. ix ----------------------------------------------------------------------------- 83  PAGE x U GEMINORUM LIGHT CURVES 1991 - 1995 ------------END OF FILE-------------------------------------------------------