Research Note IY Ursae Majoris: Accretion disc evolution after superoutburst
Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarighradsko Shousse Blvd., 1784 Sofia, Bulgaria
2 Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Brussels, Belgium
Accepted: 15 December 2000
CCD photometry of the newly discovered eclipsing dwarf nova IY Ursae Majoris is used to study the physical properties of the accretion disc in the late decline and quiescence stages. Eclipse mapping analysis shows that in these stages the accretion disc is cool with approximately flat radial brightness temperature distribution and K. The hot spot is found to lie close along the stream trajectory at distance and from the disc center in February and March. The orbital hump strength decreases by ∼30% in a month. Taking the smallest possible size of the hot spot, we derive an upper limit for its brightness temperature, ∼15 900 K and ∼13 800 K, respectively.
Key words: accretion, accretion disc / binaries: eclipsing / stars: individual: IY UMa / dwarf nova, cataclysmic variables
© ESO, 2001