The distribution of SiO in the circumstellar envelope around IRC+10216
| dc.creator | Schoeier, F. L. | |
| dc.creator | Fong, D. | |
| dc.creator | Olofsson, H. | |
| dc.creator | Zhang, Q. | |
| dc.creator | Patel, N. | |
| dc.date | 2006-05-19 | |
| dc.date.accessioned | 2026-07-07T10:39:02Z | |
| dc.date.available | 2026-07-07T10:39:02Z | |
| dc.description | New interferometric observations of SiO J=5-4 circumstellar line emission around the carbon star IRC+10216, using the Submillimeter Array, are presented. Complemented by multi-transition single-dish observations, including infrared observations of ro-vibrational transitions, detailed radiative transfer modelling suggests that the fractional abundance of SiO in the inner part of the envelope, between approximately 3-8 stellar radii, is as high as 1.5E-6. This is more than an order of magnitude higher than predicted by equilibrium stellar atmosphere chemistry in a carbon-rich environment and indicative of the importance of non-LTE chemical processes. In addition to the compact component, a spatially more extended (2.4E16 cm) low-fractional-abundance (1.7E-7) region is required to fit the observations. This suggests that the majority of the SiO molecules are effectively accreted onto dust grains in the inner wind while the remaining gas-phase molecules are eventually photodissociated at larger distances. Evidence of departure from a smooth wind is found in the observed visibilities, indicative of density variations of a factor 2 to 5 on an angular scale corresponding to a time scale of about 200 years. Additionally, constraints on the velocity structure of the wind are obtained. | |
| dc.description | Accepted for publication in ApJ, 9 pages, 9 figures | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0605485 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0605485 | |
| dc.identifier | Astrophys.J.649:965-972,2006 | |
| dc.identifier | doi:10.1086/506199 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/180891 | |
| dc.subject | Astrophysics | |
| dc.title | The distribution of SiO in the circumstellar envelope around IRC+10216 | |
| dc.type | text |