Gemini Preprint #65


The Infrared Evolution of Sakurai's Object

T. R. Geballe
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720

A. E. Evans, B. Smalley and V. H. Tyne
Physics Dept., Keele University, Keele, Staffordshire, ST5 5BG, U.K.

S. P. S. Eyres
Astrophysics Research Institute, Birkenhead, CH41 1LD, U.K.

Abstract.

Infrared spectroscopy and photometry have revealed the remarkable evolution of Sakurai's Object from 1996 to the present. A cooling, carbon-rich photospheric spectrum was observable from 1996 to 1998. Considerable changes occured in 1998 as the continuum reddened due to absorption and emission by newly formed dust located outside the photosphere. In addition, a strong and broad helium 1.083 µm P Cygni line developed, signifying the acceleration of an outer envelope of mate rial to speeds as high as 1000 km s-1. At the same time the photosphere of the central star remained quiescent. By 1999 the photosphere was virtually completely obscured by the dust and the helium emission line was the only detectable spectral feature remaining in the 1-5 µm band. In 2000 emission by dust has be come even more dominant, as the envelope continues to expand and cool and the helium line weakens.

To appear in Astrophysics and Space Science.

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Ruth A. Kneale / web@gemini.edu / November 28, 2000