| dc.creator |
Fonfría, José Pablo |
|
| dc.creator |
Cernicharo, José |
|
| dc.creator |
Richter, Matthew J. |
|
| dc.creator |
Lacy, John H. |
|
| dc.date |
2007-12-26T16:46:53Z |
|
| dc.date |
2007-12-26T16:46:53Z |
|
| dc.date |
2007-10-09 |
|
| dc.date.accessioned |
2017-01-31T00:59:32Z |
|
| dc.date.available |
2017-01-31T00:59:32Z |
|
| dc.identifier |
arXiv:0709.4390v3 |
|
| dc.identifier |
http://hdl.handle.net/10261/2611 |
|
| dc.identifier.uri |
http://dspace.mediu.edu.my:8181/xmlui/handle/10261/2611 |
|
| dc.description |
Accepted for publication in the Astrophysical Journal. |
|
| dc.description |
A spectral survey of IRC+10216 has been carried out in the range 11 to 14 um with a spectral resolution of about 4 km s^-1. We have identified a forest of lines in six bands of C2H2 involving the vibrational states from the ground to 3ν5 and in two bands of HCN, involving the vibrational states from the ground up to 2ν2. Some of these transitions are observed also in H13CCH and H13CN. We have estimated the kinetic, vibrational, and rotational temperatures, and the abundances and column densities of C2H2 and HCN between 1 and 300 R* (1.5E16 cm) by fitting about 300 of these ro-vibrational lines. The envelope can be divided into three regions with approximate boundaries at 0.019 arcsec (the stellar photosphere), 0.1 arcsec (the inner dust formation zone), and 0.4 arcsec (outer dust formation zone). Most of the lines might require a large microturbulence broadening. The derived abundances of C2H2 and HCN increase by factors of 10 and 4, respectively, from the innermost envelope outwards. The derived column densities for both C2H2 and HCN are 1.6E19 cm^-2. Vibrational states up to 3000 K above ground are populated, suggesting pumping by near-infrared radiation from the star and innermost envelope. Low rotational levels can be considered under LTE while those with J>20-30 are not thermalized. A few lines require special analysis to deal with effects like overlap with lines of other molecules. |
|
| dc.description |
J. Cernicharo and J. P. Fonfría would like to thank the Spanish Ministerio de Educación y Ciencia for funding support through grant ESP2004-665, AYA2003-2785,
and the "Comunidad de Madrid" government under PRICIT project S-0505/ESP-0237 (ASTROCAM). During this study, J. P. Fonfría was supported by the CSIC and the "Fondo Social Europeo" under internship grant from the I3P Programme. This study is supported in part by the European Community’s human potential Programme under contract MCRTN-CT-2004-51230, "Molecular Universe". M. J. Richter is supported by
grant AST-0307497. |
|
| dc.description |
Peer reviewed |
|
| dc.format |
2726012 bytes |
|
| dc.format |
application/pdf |
|
| dc.language |
eng |
|
| dc.relation |
Preprint |
|
| dc.rights |
openAccess |
|
| dc.subject |
Line: identification |
|
| dc.subject |
Line: profiles |
|
| dc.subject |
Surveys |
|
| dc.subject |
Stars: Asymptotic Giant Branch (AGB) and post-AGB |
|
| dc.subject |
Stars: carbon |
|
| dc.subject |
Stars: individual (IRC+10216) |
|
| dc.title |
A Detailed Analysis of the Dust Formation Zone of IRC+10216 Derived from Mid-IR Bands of C2H2 and HCN |
|
| dc.type |
Pre-print |
|