The earliest phases of high mass star formation, as seen in NGC 6334 by Herschel HOBYS
Author
dc.contributor.author
Tige, J.
Author
dc.contributor.author
Motte, F.
Author
dc.contributor.author
Russeil, D.
Author
dc.contributor.author
Louvet, F.
Admission date
dc.date.accessioned
2018-07-13T14:24:23Z
Available date
dc.date.available
2018-07-13T14:24:23Z
Publication date
dc.date.issued
2017
Cita de ítem
dc.identifier.citation
Astronomy & Astrophysics, 602, A77 (2017)
es_ES
Identifier
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10.1051/0004-6361/201628989
Identifier
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https://repositorio.uchile.cl/handle/2250/149850
Abstract
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Aims. To constrain models of high-mass star formation, the Herschel-HOBYS key program aims at discovering massive dense cores (MDCs) able to host the high-mass analogs of low-mass prestellar cores, which have been searched for over the past decade. We here focus on NGC 6334, one of the best-studied HOBYS molecular cloud complexes.
Methods. We used Herschel /PACS and SPIRE 70 500 mu m images of the NGC 6334 complex complemented with (sub) millimeter and mid-infrared data. We built a complete procedure to extract 0.1 pc dense cores with the getsources software, which simultaneously measures their far-infrared to millimeter fluxes. We carefully estimated the temperatures and masses of these dense cores from their spectral energy distributions (SEDs). We also identified the densest pc-scale cloud structures of NGC 6334, one 2 pc x 1 pc ridge and two 0.8 pc x 0.8 pc hubs, with volume-averaged densities of 10(5) cm(-3).
Results. A cross-correlation with high-mass star formation signposts suggests a mass threshold of 75 M-circle dot for MDCs in NGC 6334. MDCs have temperatures of 9 : 5 40 K, masses of 75 1000 M-circle dot, and densities of 1 x 10(5) 7 x 10(7) cm(-3). Their mid-infrared emission is used to separate 6 IR-bright and 10 IR-quiet protostellar MDCs while their 70 mu m emission strength, with respect to fitted SEDs, helps identify 16 starless MDC candidates. The ability of the latter to host high-mass prestellar cores is investigated here and remains questionable. An increase in mass and density from the starless to the IR-quiet and IR-bright phases suggests that the protostars and MDCs simultaneously grow in mass. The statistical lifetimes of the high-mass prestellar and protostellar core phases, estimated to be 1-7 x 10(4) yr and at most 3 105 yr respectively, suggest a dynamical scenario of high-mass star formation.
Conclusions. The present study provides good mass estimates for a statistically significant sample, covering the earliest phases of high-mass star formation. High-mass prestellar cores may not exist in NGC 6334, favoring a scenario presented here, which simultaneously forms clouds, ridges, MDCs, and high-mass protostars.
es_ES
Patrocinador
dc.description.sponsorship
CSA (Canada)
NAOC (China)
CEA (France)
CNES (France)
CNRS (France)
ASI (Italy)
MCINN (Spain)
SNSB (Sweden)
STFC (UK)
UKSA (UK)
NASA (USA)
BMVIT (Austria)
ESA-PRODEX (Belgium)
CEA/CNES (France)
DLR (Germany)
ASI/INAF (Italy)
CICYT/MCYT (Spain)
ANR (Agence Nationale pour la Recherche) project "PROBeS"
ANR-08-BLAN-0241
"Programme National de Physique Stellaire" (PNPS)
program "Physique et Chime du Milieu Interstellaire" (PCMI) of CNRS/INSU, France
Leverhulme Emeritus Professorial Fellowship