2010A&A...516A..81B


Query : 2010A&A...516A..81B

2010A&A...516A..81B - Astronomy and Astrophysics, volume 516, A81-81 (2010/6-3)

The fate of the pre-main sequence-rich clusters Collinder 197 and vdB 92: dissolution?

BONATTO C. and BICA E.

Abstract (from CDS):

Since most of the star clusters do not survive the embedded phase, their early dissolution appears to be a major source of field stars. However, catching a cluster in the act of dissolving is somewhat elusive. We investigate the nature and possible evolution of the young Galactic star clusters Collinder 197 (Cr 197) and vdB92. Photometric and structural properties were derived with near-infrared photometry and field-star decontamination. Kinematical properties were inferred from proper motions of the main sequence (MS) and pre-MS (PMS) member stars. The colour-magnitude diagrams (CMDs) are basically characterised by a poorly-populated MS and a dominant fraction (>75%) of PMS stars, and the combined MS and PMS CMD morphology in both clusters consistently constrains the age to within 5±4Myr, with a ∼10Myr spread in the star formation process. The MS+PMS stellar masses are ≃660+102–59M (Cr 197) and ≃750+101–51M (vdB 92). Both Cr 197 and vdB 92 appear to be abnormally large when compared to clusters within the same age range. They have irregular stellar radial density distributions (RDPs) with a marked excess in the innermost region, a feature that, at less than 10Myr, is more likely related to the star formation and/or molecular cloud fragmentation than to age-dependent dynamical effects. The velocity dispersion of both clusters, derived from proper motions, is in the range ∼15-22km/s. Both clusters appear to be in a super-virial state, with velocity dispersions higher than those expected of nearly-virialised clusters of similar mass and size. A possible interpretation is that Cr 197 and vdB 92 deviate critically from dynamical equilibrium, and may dissolve into the field. We also conclude that early cluster dissolution leaves detectable imprints on RDPs of clusters as massive as several 102M. Cr 197 and vdB 92 may be the link between embedded clusters and young stellar associations.

Abstract Copyright:

Journal keyword(s): open clusters and associations: general - open clusters and associations: individual: Collinder 197 - open clusters and associations: individual: vdB 92

Simbad objects: 32

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Number of rows : 32
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 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6564 1
2 NGC 1931 OpC 05 31 23 +34 14.0     10.1     ~ 123 0
3 Cl Bochum 1 OpC 06 25 18 +19 46.8   8.08 7.9     ~ 51 1
4 HD 46060 V* 06 30 49.8131054472 -09 39 14.800859892   9.03 8.82     B2II 36 0
5 NGC 2244 OpC 06 32 11 +04 54.8           ~ 608 1
6 V* Z CMa Ae* 07 03 43.1599411656 -11 33 06.209065836 10.51 9.99 8.80     B5/8eq+F5/7 560 3
7 BD-11 1761 * 07 03 52.4970988152 -11 34 51.858995628 8.83 9.32 9.25     B2V 24 0
8 BD-11 1763 Y*O 07 03 54.8581618368 -11 34 34.077428004   9.52 9.53 9.60 9.12 B1.5V 27 0
9 HRW 14 * 07 03 56.8412699400 -11 34 41.748620592 12.57 12.66 12.07 12.03   B7III 10 0
10 Cl VDB 92 OpC 07 04 09 -11 28.5           ~ 34 1
11 HD 53339 Y*O 07 04 15.8826541597 -11 24 05.693106995   9.55 9.41 10.56 9.30 B3V 22 0
12 IC 2177 RNe 07 04 25 -10 27.3           ~ 150 2
13 HD 53456 ** 07 04 38.30264 -11 31 26.6198 6.41 7.31 7.40     B1Ib/II 50 0
14 [BDS2003] 96 OpC 07 05 20 -12 19.6           ~ 22 0
15 NAME CMa OB1 As* 07 07.0 -10 28           ~ 140 0
16 NAME CMa R1 As* 07 08 21.3 -11 04 50           ~ 83 1
17 HD 54662 SB* 07 09 20.2493151288 -10 20 47.635088964 5.35 6.24 6.21 7.23   O6.5Vz(n)+O7.5Vz 334 2
18 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1192 2
19 ESO 313-7 OpC 08 37 38 -39 36.2   10.36 9.9     ~ 37 0
20 GUM 15 HII 08 43 52.5 -41 14 39           ~ 32 2
21 HD 74804 Y*? 08 44 40.3247349456 -41 16 37.974116352 7.13 9.26 8.84 8.31 9.41 B3/5II 60 1
22 ESO 313-13 OpC 08 44 48 -41 16.8   7.01 6.7     ~ 71 0
23 NAME Vela R2 As* 09 00 -43.0           ~ 25 0
24 NGC 3960 OpC 11 50 35 -55 40.7   9.07 8.3     ~ 132 0
25 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1646 0
26 NGC 4755 OpC 12 53 40 -60 22.3           ~ 286 0
27 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4165 4
28 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13453 0
29 M 16 OpC 18 18 45 -13 47.5   6.58 6.0     ~ 1006 2
30 NGC 6823 OpC 19 43 11 +23 19.3   7.71 7.1     ~ 267 2
31 NAME Ori-Cyg Arm reg 20 00 +35.0           ~ 45 0
32 [LK2002] Cl10 OpC 20 39 13 +39 58.6           ~ 6 0

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2023.02.04-18:57:48

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