J/A+A/563/A94 Kinematics of the Gamma Vel cluster (Jeffries+, 2014)
The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum cluster.
Jeffries R.D., Jackson R.J., Cottaar M., Koposov S.E., Lanzafame A.C.,
Meyer M.R., Prisinzano L., Randich S., Sacco G.G., Brugaletta E.,
Caramazza M., Damiani F., Franciosini E., Frasca A., Gilmore G.,
Feltzing S., Micela G., Alfaro E., Bensby T., Pancino E., Recio-Blanco A.,
de Laverny P., Lewis J., Magrini L., Morbidelli L., Costado M.T., Jofre P.,
Klutsch A., Lind K., Maiorca E.
<Astron. Astrophys. 563, A94 (2014)>
=2014A&A...563A..94J 2014A&A...563A..94J
ADC_Keywords: Clusters, open ; Photometry ; Equivalent widths ;
Radial velocities ; Rotational velocities
Keywords: stars: pre-main-sequence - stars: kinematics and dynamics -
open clusters and associations: individual: gamma2 Velorum -
stars: formation
Abstract:
A key science goal of the Gaia-ESO survey (GES) at the VLT is to use
the kinematics of low-mass stars in young clusters and star forming
regions to probe their dynamical histories and how they populate the
field as they become unbound. The clustering of low-mass stars around
the massive Wolf-Rayet binary system γ2 Velorum was one of the
first GES targets.
Targets were selected from colour-magnitude diagrams and intermediate
resolution spectroscopy was used to derive radial velocities and
assess membership from the strength of the LiI 6708Å line. The
radial velocity distribution was analysed using a maximum likelihood
technique that accounts for unresolved binaries.
Description:
The positions, photometry, radial velocities, projected equatorial
velocities and lithium equivalent widths for 208 members of the
Gamma2 Velorum cluster. These members were selected on the basis of
their positions in the V versus V-I colour-magnitude diagram and the
strength of lithium absorption in their spectra. The photometry is
from Jeffries et al. (2009MNRAS.393..538J 2009MNRAS.393..538J). The radial velocities,
projected equatorial velocities and equivalent widths of the 6708
angstrom LiI feature are from spectra taken with FLAMES/GIRAFFE at the
VLT as part of the Gaia-ESO spectroscopic survey. Although values of
projected equatorial velocity less than 10km/s are reported, these
should be treated as upper limits at 10km/s. Masses are estimated from
the $V-I$ colour and models of Baraffe et al. (1998A&A...337..403B 1998A&A...337..403B)
for an assumed age of 10Myr. Two kinematic populations are reported
in the paper; P(A) reports the probability that a star belongs to
population "A".
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 100 208 Coordinates, photometry and measurements of
radial velocities, equivalent widths of the
Li 6708Å line, projected equatorial velocities
and estimated masses for 208 targets selected
as γ2 Vel members
--------------------------------------------------------------------------------
See also:
J/ApJ/686/1195 : IR photometry in the γ Vel cluster (Hernandez+, 2008)
J/MNRAS/393/538 : Stellar association around γ Vel (Jeffries+, 2009)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- CName Target Name in the Gaia-ESO archive
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 28 F5.2 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 41 F5.2 arcsec DEs Declination (J2000)
43- 47 F5.2 mag Vmag Apparent V magnitude (Johnson)
49- 52 F4.2 mag V-Ic V-I colour index (Cousins)
54- 56 I3 --- SNR Signal to noise ratio of average spectrum
58 I1 --- N [1/4] Number of contributing observations
60- 65 F6.1 0.1nm EWLi Equivalent width of the 6708Å Li line
67- 71 F5.1 0.1nm e_EWLi rms uncertainty on EWLi
73- 78 F6.2 km/s HRV Mean heliocentric radial velocity
80- 83 F4.2 km/s e_HRV rms uncertainty on HRV
85- 89 F5.2 --- P(A) [0/1]?=-1 Probability of membership to
kinematic population A (1)
91- 95 F5.1 km/s vsini Projected equatorial velocity (2)
97-100 F4.2 Msun M Stellar mass (3)
--------------------------------------------------------------------------------
Note (1): the paper demonstrates that two kinematic components are present
in the radial velocity; population A is more concentrated around
γ2 Vel, and 1-2Myr older than population B.
Note (2): Values less than 10km/s should be treated as upper limits at 10km/s.
Note (3): Estimated from the V-I colour and the models of Baraffe et
al. (1998A&A...337..403B 1998A&A...337..403B).
--------------------------------------------------------------------------------
Acknowledgements:
Rob Jeffries, rdj(at)astro.keele.ac.uk
References:
Baraffe et al., 1998A&A...337..403B 1998A&A...337..403B, Evolutionary models for solar metallicity
low-mass stars: mass-magnitude relationships and color-magnitude diagrams
Jeffries et al., 2009MNRAS.393..538J 2009MNRAS.393..538J, The stellar association around Gamma
Velorum and its relationship with Vela OB2
(End) Rob Jeffries [Keele University], Patricia Vannier [CDS] 24-Jan-2014