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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20100923T000000
DTEND;TZID=Atlantic/Canary:20100923T010000
UID:iactalks-211
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/211
CREATED:2010-09-23T00:00:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Ice and organics
DESCRIPTION:Ice and organics\nDr. Javier Licandro\n\nIn this talk we presen
 t spectroscopy of asteroids 24 Themis and 65 Cybele in the 2-4 μ region
  obtained with the NASA 3.5m IRTF telescope. Their spectra are very simila
 r, and present the typical water ice band at 3.1 μ and additional absor
 ption bands in the 3.2-3.4 μ region that can be attributed to solid org
 anics, showing that there is a small amount of water ice and solid organic
 s widely distributed across their surface.\nSpectra in the 6-25 μ regio
 n obtained with SPITZER of 65 Cybele also show that its surface is covered
  by a fine anhydrous silicate grains mantle as other outer belt asteroids 
 like the Trojans are. This dust mantle, with a small amount of water ice a
 nd complex organic solids, is similar to comet surface where non-equilibri
 um phases coexist. The presence of water-ice and anhydrous silicates is in
 dicative that hydration did not happened or is incomplete, suggesting that
  the temperatures were always sufficiently low.\nThis is the first detecti
 on of water ice and and solid organics in the surface of an asteroid and s
 uggest that these materials are much more abundant than expected in the su
 rface of asteroids with semi-major axis a > 3 AU. The cosmogonical and ast
 robiological relevance of this discovery will be discussed. 
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