2010A&A...522A..40M


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.16CEST17:52:17

2010A&A...522A..40M - Astronomy and Astrophysics, volume 522, A40-40 (2010/11-1)

Tracing early evolutionary stages of high-mass star formation with molecular lines.

MARSEILLE M.G., VAN DER TAK F.F.S., HERPIN F. and JACQ T.

Abstract (from CDS):

Despite its major role in the evolution of the interstellar medium, the formation of high-mass stars (M≥10M) remains poorly understood. Two types of massive star cluster precursors, the so-called massive dense cores (MDCs), have been observed, which differ in terms of their mid-infrared brightness. The origin of this difference has not yet been established and may be the result of evolution, density, geometry differences, or a combination of these. We compare several molecular tracers of physical conditions (hot cores, shocks) observed in a sample of mid-IR weakly emitting MDCs with previous results obtained in a sample of exclusively mid-IR bright MDCs. We attempt to understand the differences between these two types of object. We present single-dish observations of HDO, H218O, SO2, and CH3OH lines at λ=1.3-3.5mm. We study line profiles and estimate abundances of these molecules, and use a partial correlation method to search for trends in the results. The detection rates of thermal emission lines are found to be very similar for both mid-IR quiet and bright objects. The abundances of H2O, HDO (10–13 to 10–9 in the cold outer envelopes), SO2 and CH3OH differ from source to source but independently of their mid-IR flux. In contrast, the methanol class I maser emission, a tracer of outflow shocks, is found to be strongly anti-correlated with the 12µm source brightnesses. The enhancement of the methanol maser emission in mid-IR quiet MDCs may be indicative of a more embedded nature. Since total masses are similar between the two samples, we suggest that the matter distribution is spherical around mid-IR quiet sources but flattened around mid-IR bright ones. In contrast, water emission is associated with objects containing a hot molecular core, irrespective of their mid-IR brightness. These results indicate that the mid-IR brightness of MDCs is an indicator of their evolutionary stage.

Abstract Copyright:

Journal keyword(s): ISM: abundances - evolution - stars: formation - line: profiles

Simbad objects: 22

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Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NAME W3 IRS 5 Y*O 02 25 40.54 +62 05 51.4           B1 322 0
2 RAFGL 490 Y*O 03 27 38.7928323987 +58 47 00.017662871           ~ 334 0
3 IRAS 05358+3543 mul 05 39 10.4 +35 45 19           ~ 131 1
4 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 2926 0
5 GRS G012.89 +00.49 HII 18 11 51.3 -17 31 29           ~ 143 0
6 W 33a Y*O 18 14 39.0 -17 52 03           ~ 570 0
7 [BSM2002] 18151-1208 2 cor 18 17 50.36 -12 07 54.8           ~ 17 0
8 IRAS 18151-1208 Y*O 18 17 58.114 -12 07 24.84           ~ 99 0
9 RAFGL 2136 SFR 18 22 26.8740 -13 30 17.177           ~ 232 0
10 IRAS 18264-1152 cor 18 29 14.6846 -11 50 23.966           ~ 70 1
11 SNR G030.8-00.0 SNR 18 47 32 -01 56.5           ~ 423 0
12 [MSL2003] W43-MM1 cor 18 47 47.0 -01 54 28           ~ 83 0
13 NAME Cyg X Cld 20 28 41 +41 10.2           ~ 586 1
14 RAFGL 2591 Y*O 20 29 25.2650 +40 11 26.532   18       ~ 562 5
15 [MBS2007c] CygX-N44 Rad 20 39 01.01 +42 22 50.2           ~ 356 0
16 [MBS2007c] CygX-N48 IR 20 39 01.36 +42 22 06.7           ~ 14 0
17 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 928 0
18 NAME SH 2-140 IRS 1 Y*O 22 19 18.277 +63 18 45.82           ~ 190 0
19 NGC 7538S Y*O 23 13 44.8 +61 26 51           ~ 72 1
20 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 359 3
21 [WBN74] NGC 7538 IRS 9 Y*O 23 14 01.63 +61 27 20.2           ~ 336 0
22 Mol 160 Rad 23 40 54.5 +61 10 28           ~ 88 0

    Equat.    Gal    SGal    Ecl

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2019.10.16-17:52:17

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