2018A&A...615A..37B


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.12CEST11:31:00

2018A&A...615A..37B - Astronomy and Astrophysics, volume 615A, 37-37 (2018/7-1)

The Gaia-ESO Survey: a kinematical and dynamical study of four young open clusters.

BRAVI L., ZARI E., SACCO G.G., RANDICH S., JEFFRIES R.D., JACKSON R.J., FRANCIOSINI E., MORAUX E., LOPEZ-SANTIAGO J., PANCINO E., SPINA L., WRIGHT N.J., JIMENEZ-ESTEBAN F.M., KLUTSCH A., ROCCATAGLIATA V., GILMORE G., BRAGAGLIA A., FLACCOMIO E., FRANCOIS P., KOPOSOV S.E., BAYO A., CARRARO G., COSTADO M.T., DAMIANI F., FRASCA A., HOURIHANE A., JOFRE P., LARDO C., LEWIS J., MAGRINI L., MORBIDELLI L., PRISINZANO L., SOUSA S.G., WORLEY C.C. and ZAGGIA S.

Abstract (from CDS):


Context. The origin and dynamical evolution of star clusters is an important topic in stellar astrophysics. Several models have been proposed in order to understand the formation of bound and unbound clusters and their evolution, and they can be tested by examining the kinematical and dynamical properties of clusters over a wide range of ages and masses.
Aims. We use the Gaia-ESO Survey products to study four open clusters (IC 2602, IC 2391, IC 4665, and NGC 2547) that lie in the age range between 20 and 50Myr.
Methods. We employ the gravity index γ and the equivalent width of the lithium line at 6708 Å together with effective temperature Teff and the metallicity of the stars in order to discard observed contaminant stars. Then we derive the cluster radial velocity dispersions σc, the total cluster mass Mtot, and the half mass radius rhm. Using the Gaia-DR1 TGAS catalogue, we independently derive the intrinsic velocity dispersion of the clusters from the astrometric parameters of cluster members.
Results. The intrinsic radial velocity dispersions derived by the spectroscopic data are higher than those derived from the TGAS data, possibly due to the different masses of the considered stars. Using Mtot and rhm we derive the virial velocity dispersion σvir and we find that three out of four clusters are supervirial. This result is in agreement with the hypothesis that these clusters are dispersing, as predicted by the "residual gas expulsion" scenario. However, recent simulations show that the virial ratio of young star clustersmay be overestimated if it is determined using the global velocity dispersion, since the clusters are not fully relaxed.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: pre-main sequence - stars: kinematics and dynamics - open clusters and associations: general - stars: formation - techniques: spectroscopic - techniques: radial velocities

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 Ass Vel OB 2 As* 08 09 22.478 -47 21 03.46           ~ 211 0
2 NGC 2547 OpC 08 09 52.360 -49 10 35.01           ~ 310 0
3 IC 2391 OpC 08 40 32 -53 02.0           ~ 714 0
4 IC 2602 OpC 10 42 58 -64 24.0           ~ 549 0
5 NAME Cha I MoC 11 06 48 -77 18.0           ~ 968 1
6 NGC 4664 GiG 12 45 05.9996914142 +03 03 20.762799716   11.50 10.50     ~ 156 1
7 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3027 0
8 IC 4665 OpC 17 46 18 +05 43.0           ~ 312 0

    Equat.    Gal    SGal    Ecl

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2020.07.12-11:31:00

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