NOAO >   Observing Info >   Approved Programs >   2001A-0063

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Proposal Information for 2001A-0063


PI: Richard R. Joyce, NOAO, joyce@noao.edu
Address: P.O. Box 26732, Tucson, Arizona 85726, USA

CoI: Kenneth Hinkle, NOAO

Title: IR Spectroscopy of Final Flash Stars

Abstract: Post-AGB stars can undergo a final episode of helium shell burning after the star has ejected a planetary nebula and has started on the white dwarf track. This final flash episode is very short lived, and hence although common, rarely observed. Starting in 1996 Sakurai's star has been observed to undergo a final helium shell flash. During the four years since the discovery of Sakurai's star, this object has demonstrated dramatic changes in elemental abundances, effective photospheric temperature, and visual magnitude. Other than catastrophic events such as supernovae, Sakurai's star is undergoing stellar evolution at a record pace. Following the ejection of a dust shell in late 1998, Sakurai's star has dimmed by more than 10 mag at V. A nearly identical series of events occurred in V605 Aql 81 years ago. It is believed that the central stars of the planetary nebulae A30 and A78 underwent final flashes some thousands of years ago. All four stars are encapsulated in dust shells of their own making. Infrared spectroscopy of these stars is required to follow their continuing evolution.


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