T. R. Geballe, Gemini Observatory, Hilo, Hawaii, USA
Infrared spectroscopy and photometry reveal the remarkable evolution of
Sakurai's Object from 1996 to the present. A cooling, carbon-rich
`photosphere' was observable from 1996 to 1998. Remarkable change was
evident in 1998 as the continuum reddened and a strong and very broad
Helium 10830Å absorption line developed, signifying the
acceleration of the outer envelope by newly forming dust. The helium
profile quickly developed a strong P Cygni-like emission component,
while at the same time much of the `photosphere' remained quiescent as
it faded from view. By 1999 the `photosphere' was virtually totally
obscured by the dust, and the helium emission line, with a width of
kms-1, was the only strong spectral feature remaining. In
2000 the dust emission has become even more dominant, as the shell
continues to expand and cool and the helium line weakens.