Robert Williams
Space Telescope Science Inst. (STScI) (Baltimore, Maryland, Etats-Unis d'Amérique)
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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| « Understanding the Nova Outburst » |
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Robert Williams |
| Spectroscopic observations of novae date back a century and the fundamental nature of the outburst has been understood for 50 years. Yet, recent observations suggest possible major modifications to the standard nova paradigm. A high-resolution spectroscopic survey of novae has revealed short-lived heavy element absorption systems near maximum light consisting of Fe-peak and s-process elements. The absorbing gas is circumbinary and it must pre-exist the outburst. Its origin appears to be mass ejection from the secondary star, implying large episodic mass transfer events from the secondary that initiate the nova outburst. The spectroscopic evolution of novae is interpreted in terms of two distinct interacting gas systems in which the bright continuum is produced by the outburst ejecta but absorption and emission lines originate in gas ejected by the secondary star in a way that may explain dust formation and X-ray emission from novae. |
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vendredi 10 avril 2009 - 11:00 Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |