A Zombie White Dwarf Star is Born Again. Hallelujah!
30 years ago, an amateur astronomer noticed a white dwarf star suddenly getting brighter. New research shows this is due to a Very Late Thermal Pulse, a type of helium flash. The star has heated up and become brighter, and is now called a 'born again' star. It's evolved into a Wolf-Rayet type star, and astronomers will get to watch as it continues to evolve on human timescales.
Stars go through many transformations throughout their lives, but those changes typically occur over vast stretches of time. Sakurai's Object, however, has undergone an extraordinary revival and is now described as being reborn, or "born again." This star, originally a main sequence star, expanded into a red giant before becoming a white dwarf, a cold, dying ember that radiates only the residual heat from its earlier life.
In 1996, amateur astronomer Yukio Sakurai noticed a powerful helium shell flash, which reignited the star and caused it to swell up and heat up again, making Sakurai's Object a rare "born again" star.
Observing stellar evolution on human timescales is exceedingly rare. Over the course of 30 years, Sakurai's Object has grown six times hotter due to this helium flash. As a white dwarf, it was inactive and cold, but now it is heating up and expanding once more. Eventually, it will likely revert to its previous state as a white dwarf.
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