dc.contributor.author |
Dinh, V. T |
|
dc.contributor.author |
Muller, S |
|
dc.contributor.author |
Lim, J |
|
dc.contributor.author |
Kwok, S |
|
dc.contributor.author |
Muthu, C |
|
dc.date.accessioned |
2009-08-28T15:12:33Z |
|
dc.date.available |
2009-08-28T15:12:33Z |
|
dc.date.issued |
2009-05-20 |
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dc.identifier.citation |
Astrophysical Journal, Vol. 697, No. 1, pp. 409 – 419 |
en |
dc.identifier.issn |
0004-637X |
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dc.identifier.uri |
http://hdl.handle.net/2248/4780 |
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dc.description |
Open Access |
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dc.description.abstract |
We have used the submillimeter array to image the molecular envelope around the yellow hypergiant IRC+10420. Our observations reveal a large and clumpy expanding envelope around the star. The molecular envelope shows a clear asymmetry in (CO)-C-12 J = 2-1 emission in the southwest direction. The elongation of the envelope is found even more pronounced in the emission of (CO)-C-13 J = 2-1 and SO J(K) = 6(5)-5(4). A small positional velocity gradient across velocity channels is seen in these lines, suggesting the presence of a weak bipolar outflow in the envelope of IRC+10420. In the higher resolution (CO)-C-12 J = 2-1 map, we find that the envelope has two components: (1) an inner shell (shell I) located between radius of about 1 '' and 2 ''; (2) an outer shell (shell II) located between 3 '' and 6 '' in radius. These shells represent two previous mass-loss episodes from IRC+10420. We attempt to derive in self-consistent manner the physical conditions inside the envelope by modeling the dust properties, and the heating and cooling of molecular gas. We estimate a mass-loss rate of similar to 9 x 10(-4) M-circle dot yr(-1) for shell I and 7 x 10(-4) M-circle dot yr(-1) for shell II. The gas temperature is found to be unusually high in IRC+10420 in comparison with other oxygen-rich envelopes. The elevated gas temperature is mainly due to higher heating rate, which results from the large luminosity of the central star. We also derive an isotopic ratio C-12/C-13 = 6. |
en |
dc.language.iso |
en |
en |
dc.publisher |
The American Astronomical Society |
en |
dc.relation.uri |
http://dx.doi.org/10.1088/0004-637X/697/1/409 |
en |
dc.rights |
© The American Astronomical Society. |
en |
dc.subject |
Circumstellar Matter |
en |
dc.subject |
ISM: Molecules |
en |
dc.subject |
Stars: AGB and Post-AGB |
en |
dc.subject |
Stars: Individual: IRC+10420 |
en |
dc.subject |
Stars: Mass Loss |
en |
dc.title |
Probing the mass-loss history of the yellow hypergiant IRC+10420 |
en |
dc.type |
Article |
en |