Variable Stars - IU Leo
Type SS Cygni-type SS Cygni-type variables increase in brightness by 2-6 mag. in V in 1-2 days and in several subsequent days return to their original brightnesses. The values of the cycle are in the range 10 days to several thousand. AAVSO Alert 346/471: September 20, 2012  Drs. Boris Gaensicke (Warwick University), Joseph Patterson (Columbia University, Center for Backyard Astrophysics), and Arne Henden (AAVSO), on behalf of a consortium of 16 astronomers, have requested the help of AAVSO observers in monitoring the ~40 cataclysmic variables in the table below in support of Hubble Space Telescope observations in the coming months. The HST COS (Cosmic Origins Spectrograph) will be carrying out far-ultraviolet spectroscopy of ~40 CVs sequentially, with the aim to measure the temperatures, atmospheric compositions, rotation rates, and eventually masses of their white dwarfs. The primary purpose of the monitoring is to know whether each target is in quiescence immediately prior to the observation window; if it is in outburst it will be too bright for the HST instrumentation. Based on the information supplied by the AAVSO the HST scheduling team will make the decision (usually) the evening before the scheduled observing time as to whether to go forward with the HST observations.
Hills Observatory: 1 January 2013 to 6 May 2018
COMETS COMETS
DEEP SKY DEEP SKY