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Multi-line Herschel/HIFI observations of water reveal infall motions and chemical segregation around high-mass protostars

hal.structure.identifierSRON Netherlands Institute for Space Research [SRON]
dc.contributor.authorVAN DER TAK, Floris
hal.structure.identifierSRON Netherlands Institute for Space Research [SRON]
dc.contributor.authorSHIPMAN, Russ
hal.structure.identifierFORMATION STELLAIRE 2019
dc.contributor.authorJACQ, T.
hal.structure.identifierFORMATION STELLAIRE 2019
dc.contributor.authorHERPIN, Fabrice
hal.structure.identifierFORMATION STELLAIRE 2019
dc.contributor.authorBRAINE, J.
hal.structure.identifierMax-Planck-Institut für Radioastronomie [MPIFR]
dc.contributor.authorWYROWSKI, Friedrich
dc.date.issued2019
dc.identifier.issn0004-6361
dc.description.abstractEn(Abridged) We use HIFI maps of the 987 GHz H2O 2(02)-1(11) emission to measure the sizes and shapes of 19 high-mass protostellar envelopes. To identify infall, we use HIFI spectra of the optically thin C18O 9-8 and H2O-18 1(11)-0(00) lines. The high-J C18O line traces the warm central material and redshifted H2O-18 1(11)-0(00) absorption indicates material falling onto the warm core. We probe small-scale chemical differentiation by comparing H2O 752 and 987 GHz spectra with those of H2O-18. Our measured radii of the central part of the H2O 2(02)-1(11) emission are 30-40% larger than the predictions from spherical envelope models, and axis ratios are <2, which we consider good agreement. For 11 of the 19 sources, we find a significant redshift of the H2O-18 1(11)-0(00) line relative to C18O 9-8. The inferred infall velocities are 0.6-3.2 km/s, and estimated mass inflow rates range from 7e-5 to 2e-2 M0/yr, with the highest mass inflow rates occurring toward the sources with the highest masses, and possibly the youngest ages. The other sources show either expanding motions or H2O-18 lines in emission. The H2O-18 1(11)-0(00) line profiles are remarkably similar to the "differences" between the H2O 2(02)-1(11) and 2(11)-2(02) profiles, suggesting that the H2O-18 line and the H2O 2(02)-1(11) absorption originate just inside the radius where water evaporates from grains, typically 1000-5000 au from the center. In some sources, the H2O-18 line is detectable in the outflow, where no C18O emission is seen. Together, the H2O-18 absorption and C18O emission profiles show that the water abundance around high-mass protostars has at least three levels: low in the cool outer envelope, high within the 100 K radius, and very high in the outflowing gas. Thus, despite the small regions, the combination of lines presented here reveals systematic inflows and chemical information about the outflows.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enAstrophysics - Astrophysics of Galaxies
dc.title.enMulti-line Herschel/HIFI observations of water reveal infall motions and chemical segregation around high-mass protostars
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201833788
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv1903.11305
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageid.A103
bordeaux.volume625
bordeaux.peerReviewedoui
hal.identifierhal-02082594
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02082594v1
bordeaux.COinSctx_ver=Z39.88-2004&amp;rft_val_fmt=info:ofi/fmt:kev:mtx:journal&amp;rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&amp;rft.date=2019&amp;rft.volume=625&amp;rft.spage=id.A103&amp;rft.epage=id.A103&amp;rft.eissn=0004-6361&amp;rft.issn=0004-6361&amp;rft.au=VAN%20DER%20TAK,%20Floris&amp;SHIPMAN,%20Russ&amp;JACQ,%20T.&amp;HERPIN,%20Fabrice&amp;BRAINE,%20J.&amp;rft.genre=article


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