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Physics & Astronomy Seminar: On the Formation of AM CVn Stars
January 31 @ 3:30 pm
Dept. of Physics & Astronomy
AM CVn stars are a type of ultra-short period binary system (with orbital periods as low as 5 minutes) with a white dwarf accreting helium from a hydrogen-depleted donor star. Due to these very short periods, AM CVn stars are an excellent source of low-frequency gravitational waves (GW) that will be easily detected by the planned Laser Interferometer Space Antenna (LISA). Thanks to the Gaia mission, there are now precise observations of the properties of at least one AM CVn, which can be used to calibrate LISA. There are three potential formation channels for AM CVn stars: a double white dwarf system in which GW drives the angular momentum loss and forces the white dwarfs into contact, an evolved cataclysmic variable (CV) system where GW and magnetic braking drive the angular momentum losses, and a system where the donor star is a relatively unevolved, helium-burning core where all the hydrogen from the surface has been stripped off (known as a helium star). My research focuses mainly on the helium star formation scenario of AM CVn stars and should help to determine which known AM CVn stars can be explained by this channel and will hopefully help us understand how probable the other two formation channels are.