IP Pegasi is a U Geminorum star (dwarf nova) that is also an eclipsing binary with an orbital period of 3.80 hours. It contains a 1.02 solar mass white dwarf and a 0.5 solar mass red dwarf companion, which feeds the white dwarf's accretion disk. IP Pegasi undergoes disk instabilities causing dwarf nova disk outbursts approximately every 3 months. It is one of the few eclipsing U Gem systems for which the inclination of the orbital plane is large enough for the companion star to eclipse the white dwarf primary, the accretion disk, and the hot spot (the place where the gas stream hits the outer of edge of the accretion disk). The study of its deep eclipses has provided valuable information on the evolution of accretion disks and the mechanism of outbursts in cataclysmic variables.
Related categories NOTABLE STARS
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