The continuing saga of Sakurai's object (V4334 Sgr): dust production and helium line emission |
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| Authors: | V H Tyne S P S Eyres T R Geballe A Evans B Smalley H W Duerbeck M Asplund |
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| Institution: | Physics Department, Keele University, Keele, Staffordshire ST5 5BG;Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD;Gemini Observatory, 670 N. A'ohōkūPlace, Hilo, HI 96720, USA;Free University Brussels (VUB), Pleinlaan 2, B-1050 Brussels, Belgium;Uppsala Astronomiska Observatorium, Box 515, SE-751 20 Uppsala, Sweden |
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| Abstract: | We report further UKIRT spectroscopic observations of Sakurai's object (V4334 Sgr) made in 1999 April/May in the 1–4.75 μm range, and find that the emission is dominated by amorphous carbon at T d~600 K. The estimated maximum grain size is 0.6 μm, and the mass lower limit is 1.7±0.2×10?8 M⊙ to 8.9±0.6×10?7 M⊙ for distances of 1.1–8 kpc. For 3.8 kpc the mass is 2.0±0.1×10?7 M⊙.
We also report strong He i emission at 1.083 μm, in contrast to the strong absorption in this line in 1998. We conclude that the excitation is collisional, and is probably caused by a wind, consistent with the P Cygni profile observed by Eyres et al. in 1998. |
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| Keywords: | stars: AGB and post-AGB circumstellar matter stars: individual: Sakurai's object stars: individual: V4334 Sgr infrared: stars |
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