Other
Scientific paper
Jan 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010aas...21560640s&link_type=abstract
American Astronomical Society, AAS Meeting #215, #606.40; Bulletin of the American Astronomical Society, Vol. 36, p.1136
Other
Scientific paper
We present Spitzer Space Telescope spectroscopy of the CO2 ice absorption feature at 15.2 um toward 40 high-mass young stellar objects in the Large Magellanic Cloud. The ices that create the absorption features reside in mixtures with other solid-state species in the cold outer regions of massive YSOs' circumstellar envelopes. Observed toward both quiescent dark clouds and active regions of star formation, this particular feature displays an intriguing range of shapes; along lines of sight toward background extincted stars, the band is relatively smooth, however in regions of star formation that trace more processed material, the feature shows a pronounced double peak. These profile differences are attributed to thermal processing of the ice that may cause compositional changes to the ice mixture. Thus the shape of the CO2 absorption profile is a measure of both the composition and thermal history of the ice. We have performed a decomposition of the spectral profiles to determine the nature of the CO2 ice. Many of the LMC sources have the pronounced double peak in their CO2 feature profiles. This shape represents the first direct detections of the characteristic double peak from pure CO2 in an extragalactic environment. We find that a majority of the CO2 is embedded in a polar ice matrix, but that there are variations in the spectral shape that likely arise from the degree of the envelope ices' thermal processing. Results of the decomposition indicate that massive YSOs have warmed a substantially larger fraction of their envelopes than their lower-mass counterparts. By comparing the decomposition results to models of circumstellar envelopes, we can make estimates about envelope thermal structure and distribution. We also find evidence of an enhanced CO2 abundance in the LMC relative to the Milky Way.
Chen Rebecca
Chu Yan-Yi
Gruendl Robert A.
Looney Leslie W.
Seale Jonathan P.
No associations
LandOfFree
The Evolution of Massive YSOs in the LMC. Part II. Thermal Processing of Circumstellar Ices does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Evolution of Massive YSOs in the LMC. Part II. Thermal Processing of Circumstellar Ices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Evolution of Massive YSOs in the LMC. Part II. Thermal Processing of Circumstellar Ices will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1888320