Magnetic activity phenomena in dwarf m and k stars

Abstract

During the preparation of this thesis I received a great deal of support from many sources. It is impossible to mention everyone by name, but I wish to mention some of the people who helped to make this thesis possible. Primarily I would like to thank the Department of Education for Northern Ireland for generous financial support through the scholarship awarded to me by the Management Committee of Armagh Observatory. I express my gratitude to my thesis supervisor Dr. Gerry Doyle for suggesting the subject, his constant direction and friendship. Thanks to my University supervisor Prof. Arthur Kingston for his continual support on this work. I extend my thanks to the astronomers of Armagh Observatory Drs. Mart de Groot, P.B. Byrne, A.D. Andrews, C.J. Butler, postdocs P.M. Panagi, E. Houdebine and my fellow Ph.D. student A.C. Lanzafame for many interesting discussions. My thanks to H.M. Murphy and P.J.F. Brown for their assistance with the computer software and hardware. I acknowledge the support provided by STARLINK which is funded by the UK SERC. I also acknowledge the advice received from Drs. H.J. Walker and D.C. Parsons of RAL on handling the IRAS data. I wish to thank Poly for her encouragement and moral support throughout the preparation of this thesis. Finally and most importantly I want to thank my parents for their love, continual support and encouragement without whom this work would have no meaning. 4 2.2.4 M-dwarfs with Balmer lines in emission 48 2.2.5 M dwarfs with weak or no Ha 51 2.2.6 Do M dwarfs with no chromospheres exist ? 52 2.3 H7 versus X-ray emission in 'quiescent' and eruptive phenomena in M dwarfs 54 3 Optical Flare Activity 64 3.1 Discovery of flare activity on Gl 375 and Gl 431 64 3.1.