Sakurai's Object

Sakurai's Object (V4334 Sgr) in the constellation of Sagittarius, an object discovered to behave as a "slow nova" by Yukio Sakurai, a Japanese amateur astronomer, in 1996. [ [http://www.ing.iac.es/PR/newsletter/news2/sakurai.html THE ING NEWSLETTER No. 2, March 2000, Don Pollacco, QUB] ] It is believed to have been an asymptotic giant branch star that has undergone a final Helium flash relieving it from its atmosphere to become a white dwarf. [ [http://www.gemini.edu/index.php?option=content&task=view&id=220 Gemini Observatory] , Some Rare Abnormal Stars may have White Dwarf Parents to Blame – January 9, 2007]

Sakurai's Object is largely believed to be a red giant star that was previously a white dwarf. The Very Late Thermal Pulse (VLTP) occurred during the white dwarf phaseand swelled it up to giant size (due to the thermal pulse). These types of objects, of which only a handful have been observed, become hydrogen deficient and enrichedin Helium and other metals (Lawlor & MacDonald, 2003). It is then expected that thesewill end up as a DB, or helium rich, white dwarf after retracing its evolution track from the "born-again" giant phase back to the white dwarf cooling track. Other observed"born-again" objects include V605 Aql and FG Sge.

References

Lawlor T. M., MacDonald J., 2003, ApJ, 583, 913

See also

* V605 Aquilae