Optical Studies of X-ray Peculiar Chromospherically Active Stars THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY (PHYSICS) Investigator: Jeewan Chandra Pandey ARIES, Naini Tal Supervisor: Co-Supervisor: Prof. Ram Sagar Prof. K. P. Singh ARIES TIFR Naini Tal - 263 129 Mumbai - 400 005 Submitted to Kumaun University, Naini Tal August, 2005 DECLARATION I hereby declare that the work presented in this thesis is a result of the work carried out by me at the Aryabhatta Research Institute of Observational Sciences (ARIES), Naini Tal, under the joint supervision of Prof. Ram Sagar (Aryabhatta Research Institute of observa- tional Seiences (ARIES), Naini Tal) and Prof. K. P. Singh (Tata Institute of Fundamental Research (TIFR), Mumbai). This work has not been submitted for the award of any degree, diploma, associateship, fellowship, etc. of any other University or Institute. Place : Naini Tal Date : , 2005 Jeewan Chandra Pandey CERTIFICATE FROM THE SUPERVISOR AND CO-SUPERVISOR This is to certify that 1. The thesis entitled “Optical studies of X-ray peculiar choromospherically active stars” for the award of the degree of Doctor of Philosophy in Physics was ap- proved by the Kumaun University, Naini Tal, as per Academic Council Resolution dated 07 August, 2003, letter number 43/Physics/4/2003. 2. This thesis embodies the work of Mr. Jeewan Chandra Pandey himself. 3. Mr. Jeewan Chandra Pandey worked under us on this thesis for not less than twenty months commencing from the date of his application to Kumaun Uni- versity, Naini Tal for registration as candidate for the Ph. D. degree. He has put up at least 200 days of attendance at the Aryabhatta Research Institute of Observational Sciences (ARIES), Naini Tal during this period. 4. This thesis has not been submitted for the award of any degree, diploma, associ- ateship, fellowship, etc., of any other University or Institute. Prof. Ram Sagar Prof. K. P. Singh (ARIES, Naini Tal) (TIFR, Mumbai) (Supervisor) (Co-Supervisor) Place: Naini Tal Place: Mumbai Date : , 2005 Date : , 2005 To Who always encourage me to do what I love, Support my efforts without question, And only expect one thing in return, That I be a gentle person. (My parents) Acknowledgements I express my deep respect and gratefulness to my supervisor Prof. Ram Sagar and co-supervisor Prof. K. P. Singh for their supervision, encouragement, inspiration and mo- tivation. Without their support it would not have been possible to finish this thesis. Prof. Ram Sagar's ideas and unique way of enthusiasm are gratefully acknowledged. Prof. K. P. Singh has introduced me X-ray astronomy. His valuable criticism and suggestions are gratefully acknowledged. Comments and suggestions given by Dr. S. A. Drake at various stages of this work are highly acknowledged. I am highly grateful to Dr. Vijay Mohan and Dr. A. K. Pandey for the various scientific discussions. I also thank to Drs. B. S. Rautela, G. C. Joshi and B. B. Sanwal for various discussion. Thanks are extended to entire faculty and staff of ARIES, who are directly and indirectly responsible for this work. I am thankful to Prof. A. R. Rao, Prof. H. M. Antia, Dr. D. K. Ojha, Dr. B. Paul and Prof. S. K. Ghosh for the discussions on various issues. I also thank to Prof. A. V. Raveendran for the discussions through mails. I am highly thankful to my seniors Drs. Alok, Nilakshi, Ramakant, Santosh, Stalin and Yogesh for their help and company during initial stage of my research. The discussions on various scientific topics with Dr. Brijesh are sincerely acknowledged. The student seminars organised by him are useful and enjoyable. I greatly appreciate my batch-mate Shashi for the various discussions, helps and fun on many occasions. I am thankful to my friends Bhuwan, Kuntal, Saurabh and Umesh for their cherish company and the discussion on the variety of their research topics. I am also thankful to Dr. Amitesh, Atish, Dr. David, KK, Ramesh, Sneh and Tejbir for their company and discussion on various issues. I thank to my other friends at ARIES particularly Arti, Amitava, Himali, Kumar, Raman, Manash, Prashant and Saurav for the fun we had. Thanks to Dr. Anandmayi, Uddipan and Surajit for their various helps and fun during my TIFR stay. Much thanks to Vikram for his help in X-ray data reduction and other scientific discussions. A special thank to Girish for his various generous helps and making me feel at home at work. I also thank the Department of Astronomy and Astrophysics of TIFR for the facilities given to me during my visits to TIFR. The technical staffs at the 104-cm telescope particularly Nautiyal ji, library, computer section particularly Navin Kishor ji, electronic section and optics section of ARIES are sincerely acknowledged. I am also thankful to technical staff and the observers of Vainu Bappu Observatory for their help during the observations at VBT. This research had made use of many public domain softwares and databases. The entire teams of ROSAT X-ray observatory, 2MAAS, IRAF, FTOOLS and Starlinks are sincerely acknowledged. I would like to take this opportunity to express my deepest gratitude to my parents, my brothers Rajesh and Tribhuwan, sister Mannu, brother in law and all family members for all their love, affection and moral support. Without their constant encouragement I would not have been able to reach here. (Jeewan Ch. Pandey) List Of Publications Refereed Journals: 1. Unravelling the nature of HD 81032 - A new RS CVn binary. J. C. Pandey, K. P. Singh, S. A. Drake & R. Sagar, 2005, JAAp, Submitted 2. A Optical and X-ray studies of Chromospherically active stars FR Cnc, HD 95559 and LO Pegasi J. C. Pandey, K. P. Singh, S. A. Drake & R. Sagar, 2005, AJ, 130, 3/asto-ph 0506010 3. ARIES Imaging Polarimeter. B. S. Rautela, G. C. Joshi & J. C. Pandey, 2004, BASI, 32, 159. 4. FR Cnc = BD +16 1753 - A Young Active Main-Sequence Star. J. C. Pandey, K. P. Singh, R. Sagar & S. A. Drake, 2002, IBVS, 5351. 5. Photometric Variability of Four Coronally Active Stars. J. C. Pandey, K. P. Singh, R. Sagar & S. A. Drake, 2002, JAAp, 23, 9. Proceedings: 6. HD 81032: A newly discovered RS CVn J. C. Pandey , K. P. Singh, R. Sagar & S. A. Drake, 2005, in Proceedings of ASI 7. FR Cnc - A Young Spotted star. J. C. Pandey, 2003, BASI, 31, 329. 8. Photometric Variability of Four Coronally Active Stars. J. C. Pandey , K. P. Singh, R. Sagar & S. A. Drake, 2002, in proceedings of the i ii 'MULTI COLOUR UNIVERSE', eds. R. K. Manchanda & B. Paul, 2002, p237[ISBN 81-88513-00-8], p58. Additional Pubilcations Refereed Journals: 1. SS 433: Results of a Recent Multi-wavelength Campaign S. K. Chakrabarti, B. G. Anandarao, S. Pal, S. Mondal, A. Nandi, A.Bhattacharyya, Samir Mandal, R. Sagar, J. C. Pandey, A. Pati & S. K. Saha, 2005, MNRAS, in press/astro-ph 0501285. 2. Optical observations of the bright long duration peculiar GRB 021004 afterglow. S. B. Pandey, D. K. Sahu, L. Resmi, R. Sagar, G. C. Anupama, D. Bhattacharya, V. Mohan, T. P. Prabhu, B. C. Bhatt, J. C. Pandey, Padmakar Parihar & A. J. Castro- Tirado, 2003, BASI, 31, 19. 3. A flattening in the Optical Light Curve of SN 2002ap. S. B. Pandey, G. C. Anupama, R. Sagar, D. Bhattacharya, D. K. Sahu & J. C. Pandey, 2003, MNRAS, 340, 375. Non-refereed Journals: 4. Observation of Leonid meteor sower from Naini Tal (India) Nilakshi, K. Upadhyay , S. B. Pandey, J. C. Pandey & Sneh Lata 2000, WGN Journal of the International Meteor Organization, 28, 41. Circular: 1. GRB 011030, R-band observations. V. Mohan, S. B. Pandey, J. C. Pandey et al., 2002, GCN 1120. iii Abbriviation and Notation Abbriviation 2MASS Two Micron All-Sky-Survey BC Bolometric correction BY Dra BY Draconis CABS Chromospherically Active Binary System CCD Charge Coupled Device CVs Cataclysmic Variables CZ Convective Zone ESS Einstein Slew Survey EW Equivalent Width FK Com FK Comae Berences FR Cnc FR Cancri HWP Half-Wave Plate IRAF Image Reduction and Analysis Facility Jy Jansky LO Peg LO Pegasi MEKAL Mewe-Kaastra-Leidahl mJy milli-Jansky MS Main-sequence NIR Near Infra-red OMR Opto-Mechanic Research PMS Pre-Main-sequence RASS ROSAT All-Sky Survey ROSAT ROntgen SATellite RS CVn RS Cannum Venaticorum PET Photon Event Table PHA Pulse Height Amplitude PI Pulse Invariant PSPC Position Sensitive Proportional Counter W UMa W Ursa Majoris (W UMa) iv Notation B Johnson B band magnitude Fx X-ray Flux Frad Radio Flux I Cousin I band magnitude Lbol Bolometric Luminosity Lrad Radio Luminosity Lx X-ray Luminosity L Solar Luminosity Mbol Absolute bolometric magnitude MV Absolute V band magnitude M Mass of Sun M Mass of star ∗ P Period p Degree of polarization R Cousin R band magnitude RV Radial velocity Sx X-ray surface luminosity Srad radio surface luminosity R Sun's radius R Star's radius ∗ Teff Effective temperature U Johnson U band magnitude V Johnson V band magnitude λ Wavelength π Parallax τc Convective turnover time ! Angular velocity Ω Diferential Roattion v µα Proper motion in RA µδ Proper motion in DEC θmin Phase minimum θ Angle of polarization σ Standard deviation Contents 1 Introduction 2 1.1 The Sun and solar activity . 2 1.2 Late-type stars . 4 1.3 Chromospherically active binary stars (CABS) . 5 1.4 Stellar activity . 6 1.4.1 Starspots: A photospheric feature . 6 1.4.2 Effects of activity on photometric colour . 8 1.4.3 Spot cycle and differential rotation . 8 1.4.4 Chromospheric and transition region activity . 9 1.4.5 Coronal X-ray emission .