2012A&A...539A.156G


Query : 2012A&A...539A.156G

2012A&A...539A.156G - Astronomy and Astrophysics, volume 539A, 156-156 (2012/3-1)

The Herschel view of the on-going star formation in the Vela-C molecular cloud.

GIANNINI T., ELIA D., LORENZETTI D., MOLINARI S., MOTTE F., SCHISANO E., PEZZUTO S., PESTALOZZI M., DI GIORGIO A.M., ANDRE P., HILL T., BENEDETTINI M., BONTEMPS S., DI FRANCESCO J., FALLSCHEER C., HENNEMANN M., KIRK J., MINIER V., NGUYEN LUONG Q., POLYCHRONI D., RYGL K.L.J., SARACENO P., SCHNEIDER N., SPINOGLIO L., TESTI L., WARD-THOMPSON D. and WHITE G.J.

Abstract (from CDS):

As part of the Herschel guaranteed time key programme ``HOBYS'', we present the PACS and SPIRE photometric survey of the star-forming region Vela-C, one of the nearest sites of low-to-high-mass star formation in the Galactic plane. Our main objectives are to take a census of the cold sources and to derive their mass distribution down to a few solar masses. Vela-C was observed with PACS and SPIRE in parallel mode at five wavelengths between 70µm and 500µm over an area of about 3 square degrees. A photometric catalogue was extracted from the detections in each of the five bands, using a threshold of 5σ over the local background. Out of this catalogue we selected a robust sub-sample of 268 sources, of which ∼75% are cloud clumps (diameter between 0.05pc and 0.13pc) and 25% are cores (diameter between 0.025pc and 0.05pc). Their spectral energy distributions (SEDs) were fitted with a modified black body function. We classify 48 sources as protostellar, based on their detection at 70µm or at shorther wavelengths, and 218 as starless, because of non-detections at 70µm. For two other sources, we do not provide a secure classification, but suggest they are Class0 protostars. From the SED fitting we derived key physical parameters (i.e. mass, temperature, bolometric luminosity). Protostellar sources are in general warmer (<T≥12.8K) and more compact (<diameter≥0.040pc) than starless sources (<T≥10.3K, <diameter≥0.067pc). Both these findings can be ascribed to the presence of an internal source(s) of moderate heating, which also causes a temperature gradient and hence a more peaked intensity distribution. Moreover, the reduced dimensions of protostellar sources may indicate that they will not fragment further. A virial analysis of the starless sources gives an upper limit of 90% probability for the sources to be gravitationally bound and therefore prestellar in nature. A luminosity vs. mass diagram of the two populations shows that protostellar sources are in the early accretion phase, while prestellar sources populate a region of the diagram where mass accretion has not started yet. We fitted a power law N(logM)∝M–1.1±0.2 to the linear portion of the mass distribution of prestellar sources. This is in between that typical of CO clumps and those of cores in nearby star-forming regions. We interpret this as a result of the inhomogeneity of our sample, which is composed of comparable fractions of clumps and cores.

Abstract Copyright:

Journal keyword(s): ISM: individual objects: Vela-C - ISM: clouds - stars: formation - submillimeter: ISM - circumstellar matter

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 654 2
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4096 0
3 NAME Ori A MoC 05 38 -07.1           ~ 2897 0
4 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1191 2
5 NAME Vela-D Molecular Cloud MoC 08 39 -41.0           ~ 46 0
6 NAME VELA MOL RIDGE MoC 08 53 -45.0           ~ 144 0
7 RCW 34 HII 08 56 28.1 -43 05 58   10.5 11.21     ~ 94 0
8 NAME Vela C Cld 08 57 -43.2           ~ 160 0
9 RCW 36 HII 08 59 00.9 -43 44 10     15.20     ~ 142 0
10 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3446 1
11 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 1049 2
12 NAME Aql Rift DNe 18 32 -01.0           ~ 297 1
13 NAME Vela Field reg ~ ~           ~ 168 0

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2023.02.01-20:35:34

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