Observations of water with Herschel/HIFI toward the high-mass protostar AFGL 2591
| hal.structure.identifier | Center for Advanced Radiation Sources [University of Chicago] [CARS] | |
| dc.contributor.author | CHOI, Y., | |
| hal.structure.identifier | SRON Netherlands Institute for Space Research [SRON] | |
| dc.contributor.author | VAN DER TAK, F. F. S., | |
| hal.structure.identifier | Max-Planck-Institut für Extraterrestrische Physik [MPE] | |
| hal.structure.identifier | Leiden Observatory [Leiden] | |
| dc.contributor.author | VAN DISHOECK, E. F., | |
| hal.structure.identifier | FORMATION STELLAIRE 2015 | |
| dc.contributor.author | HERPIN, Fabrice | |
| hal.structure.identifier | Max-Planck-Institut für Radioastronomie [MPIFR] | |
| dc.contributor.author | WYROWSKI, F., | |
| dc.date.issued | 2015 | |
| dc.identifier.issn | 0004-6361 | |
| dc.description.abstractEn | Water is a sensitive tracer of physical conditions in star-forming regions because of its large abundance variations between hot and cold regions. We use spectrally resolved observations of rotational lines of H$_2$O and its isotopologs with Herschel/HIFI to constrain the physical conditions of the water emitting region toward the high-mass protostar AFGL2591. We use analytical estimates and rotation diagrams to estimate T$_{ex}$ and column densities of H$_2$O of the envelope, the outflow, and a foreground cloud. Furthermore, we use the non-LTE radiative transfer code to estimate the temperature and volume density of the H$_2$O emitting gas. Assuming LTE, we estimate an T$_{ex}$ of 42 K and a column density of 2$\times$10$^{14}$ cm$^{-2}$ for the envelope and 45 K and 4$\times$10$^{13}$ cm$^{-2}$ for the outflow, in beams of 4" and 30", respectively. Non-LTE models indicate a kinetic temperature of 60-230 K and a volume density of 7$\times$10$^6$-10$^8$ cm$^{-3}$ for the envelope, and a kinetic temperature of 70-90 K and a gas density of 10$^7$-10$^8$ cm$^{-3}$ for the outflow. The o/p ratio of the foreground absorption is 1.9$\pm$0.4, suggesting a low temperature. In contrast, the o/p ratio seen in absorption by the outflow is 3.5$\pm$1.0, as expected for warm gas. The water abundance in the envelope is 10$^{-9}$, similar to the low values found for other high- and low-mass protostars, suggesting that this abundance is constant during the embedded phase of high-mass star formation. The water abundance in the outflow is 10$^{-10}$, which is 10$\times$ lower than in the envelope and in the outflows of high- and low-mass protostars. Since beam size effects can only increase this estimate by a factor of 2, we suggest that the water in the outflow is affected by dissociating UV radiation due to the low extinction in the outflow lobe. | |
| dc.language.iso | en | |
| dc.publisher | EDP Sciences | |
| dc.subject.en | Astrophysics | |
| dc.subject.en | Astrophysics of Galaxies | |
| dc.title.en | Observations of water with Herschel/HIFI toward the high-mass protostar AFGL 2591 | |
| dc.type | Article de revue | |
| dc.identifier.doi | 10.1051/0004-6361/201322717 | |
| dc.subject.hal | Physique [physics]/Astrophysique [astro-ph] | |
| dc.identifier.arxiv | 1412.4818 | |
| bordeaux.journal | Astronomy and Astrophysics - A&A | |
| bordeaux.page | id.A85 | |
| bordeaux.volume | 576 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-01098169 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Internationale | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-01098169v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2015&rft.volume=576&rft.spage=id.A85&rft.epage=id.A85&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=CHOI,%20Y.,&VAN%20DER%20TAK,%20F.%20F.%20S.,&VAN%20DISHOECK,%20E.%20F.,&HERPIN,%20Fabrice&WYROWSKI,%20F.,&rft.genre=article |
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