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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20091120T000000
DTEND;TZID=Atlantic/Canary:20091120T010000
UID:iactalks-19
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/19
CREATED:2009-11-20T00:00:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:The nova outburst: a changing paradigm
DESCRIPTION:The nova outburst: a changing paradigm\nDr. Robert Williams\n\n
 Spectroscopic observations of novae date back a century, and the fundament
 al nature of the outburst has been understood for 50 years. Yet, recent ob
 servations suggest possible major modifications to the standard nova parad
 igm. A high-resolution spectroscopic survey of novae has revealed short-li
 ved heavy element absorption systems near maximum light consisting of Fe-p
 eak 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 se
 condary star, implying large episodic mass transfer events from the second
 ary that initiate the nova outburst. The spectroscopic evolution of novae 
 is interpreted in terms of two distinct interacting gas systems in which t
 he bright continuum is produced by the outburst ejecta but absorption and 
 emission lines originate in gas ejected by the secondary star in a way tha
 t may explain dust formation and X-ray emission from novae.
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