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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20140401T123000
DTEND;TZID=Atlantic/Canary:20140401T133000
UID:iactalks-629
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/629
CREATED:2014-04-01T12:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:R Coronae Borealis stars and their dust
DESCRIPTION:R Coronae Borealis stars and their dust\nDr. Neelamraju Kameswa
 ra Rao\n\nR Coronae Borealis (RCB) stars are the more prominent group&nbsp
 ; of high luminosity hydrogen deficient stars that are rich in carbon&nbsp
 ; and helium. They also show characteristic irregular light drops of 
  several magnitudes (between 3 and 8 magnitudes) at unpredictable  ti
 mes, caused by expulsion of self-made clouds of dust. They range in  
 surface temperatures from 4500 K to  20000 K. Some of them seem to&nb
 sp; have made even such complex molecules like fullerenes (C60) in their&n
 bsp; circumstellar regions. Neither their evolutionary history nor the dus
 t  formation mechanism are well understood. Two scenarios that have b
 een  suggested are that the present stars are a result of merger of t
 wo  white dwarfs (CO+He) or a post born-again (AGB) giant that is&nbs
 p; surviving after a final helium shell flash. The talk would describe&nbs
 p; the RCB properties and highlight the problems and challenges they pose&
 nbsp; in understanding their origins and dust production.
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