It is thought to have been a main-sequence star of spectral type A0V with around three times the mass of the Sun that has aged and passed through a red-giant phase , leaving a dense , hot remnant that has around 70 % of the Sun 's mass and a surface temperature of 17280 K . It is thought to be around 600 million years old , including both its life as a main-sequence star and white dwarf stellar remnant .
It may once have been a main sequence star of spectral type A0V with around three times the mass of the Sun .