J/MNRAS/533/705 Young groups and clusters from GES and Gaia EDR3 (Wright+, 2024)
The Gaia-ESO Survey:
3D dynamics of young groups and clusters from GES and Gaia EDR3.
Wright N.J., Jeffries R.D., Jackson R.J., Sacco G.G., Arnold B.,
Franciosini E., Gilmore G., Gonneau A., Morbidelli L., Prisinzano L.,
Randich S., Worley C.C.
<Mon. Not. R. Astron. Soc. 533, 705-728>
=2024MNRAS.533..705W 2024MNRAS.533..705W (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Clusters, open ; Stellar distribution ;
Stars, pre-main sequence
Keywords: stars: formation - stars: kinematics and dynamics
Abstract:
We present the first large-scale 3D kinematic study of ∼2700
spectroscopically confirmed young stars (<20Myr) in 18 star clusters
and OB associations (hereafter groups) from the combination of Gaia
astrometry and Gaia-ESO Survey spectroscopy. We measure 3D velocity
dispersions for all groups, which range from 0.61 to 7.4km/s (1D
velocity dispersions of 0.35-4.3km/s). We find the majority of groups
have anisotropic velocity dispersions, suggesting they are not
dynamically relaxed. From the 3D velocity dispersions, measured radii,
and estimates of total mass, we estimate the virial state and find
that all systems are super-virial when only the stellar mass is
considered, but that some systems are sub-virial when the mass of the
molecular cloud is taken into account. We observe an approximately
linear correlation between the 3D velocity dispersion and the group
mass, which would imply that the virial state of groups scales as the
square root of the group mass. However, we do not observe a strong
correlation between virial state and group mass. In agreement with
their virial state, we find that nearly all of the groups studied are
in the process of expanding and that the expansion is anisotropic,
implying that groups were not spherical prior to expansion. One group,
Rho Oph, is found to be contracting and in a sub-virial state (when
the mass of the surrounding molecular cloud is considered). This work
provides a glimpse of the potential of the combination of Gaia and
data from the next generation of spectroscopic surveys.
Description:
We present a sample of ∼2500 young stars in 18 young star clusters and
OB associations with spectroscopically-confirmed youth and 3D
kinematics.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
data.dat 297 2683 Sample of young stars with kinematics
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Byte-by-byte Description of file: data.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg Right Ascension (ICRS) at Ep=2016.0
12- 21 F10.6 deg DEdeg Declination (ICRS) at Ep=2016.0
23 A1 --- Fpos [G2] G for (ICRS) at Ep=2016.0,
2 for J2000 (1)
25- 33 F9.6 mag Gmag ? Gaia G-band photometric magnitude
35- 42 F8.6 mag e_Gmag ? Gaia G-band photometric error
44- 52 F9.6 mag BPmag ? Gaia BP-band photometric magnitude
54- 61 F8.6 mag e_BPmag ? Gaia BP-band photometric error
63- 71 F9.6 mag RPmag ? Gaia RP-band photometric magnitude
73- 80 F8.6 mag e_RPmag ? Gaia RP-band photometric error
82- 87 F6.3 mag Jmag ? 2MASS J-band photometric magnitude
89- 93 F5.3 mag e_Jmag ? 2MASS J-band photometric error
95-100 F6.3 mag Hmag ? 2MASS H-band photometric magnitude
102-106 F5.3 mag e_Hmag ? 2MASS H-band photometric error
108-113 F6.3 mag Kmag ? 2MASS K-band photometric magnitude
115-119 F5.3 mag e_Kmag ? 2MASS K-band photometric error
121-123 A3 --- fNIR 2MASS Near-IR photometric quality flag
125-132 F8.3 km/s RV ? Radial velocity
134-139 F6.3 km/s e_RV ? Radial velocity error
141-145 I5 K Teff ? Effective temperature
147-150 I4 K e_Teff ? Effective temperature error
152-155 A4 --- f_Teff Flag indicating how Teff was calculated (2)
157-160 F4.2 [cm/s2] logg ? Spectroscopic surface gravity
162-165 F4.2 [cm/s2] e_logg ? Spectroscopic logg error
167-171 F5.3 --- Gamma ? Spectroscopic Gamma index
173-177 F5.3 --- e_Gamma ? Spectroscopic Gamma index error
179-183 F5.3 --- Tau ? Spectroscopic Tau index
185-189 F5.1 0.1nm EWLi ? Equivalent Width for the Li 6708 line
191-195 F5.2 0.1nm e_EWLi ? Equivalent Width for the Li 6708 line error
196-202 F7.3 0.1nm FWZIHa ? Full-Width at Zero Intensity of Halpha
204-208 F5.3 0.1nm e_FWZIHa ? Full-Width at Zero Intensity of Halpha error
210-216 F7.3 0.1nm EWHa ? Equivalent Width of H-alpha
218-222 F5.3 0.1nm e_EWHa ? Equivalent Width of H-alpha error
224-230 F7.3 0.1nm Ha10 ? Width of H-alpha at 10%
232-238 F7.3 0.1nm e_Ha10 ? Width of H-alpha at 10% error
240-246 F7.2 km/s vsini ? Rotational velocity
248-254 F7.2 km/s e_vsini ? vsini error
256-262 F7.4 mas plx ? Gaia parallax
264-269 F6.4 mas e_plx ? Gaia parallax error
271-277 F7.3 mas/yr pmRA ? Proper motion in Right Ascension
279-283 F5.3 mas/yr e_pmRA ? Proper motion in Right Ascension error
285-291 F7.3 mas/yr pmDE ? Proper motion in Declination
293-297 F5.3 mas/yr e_pmDE ? Proper motion in Declination error
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Note (1): Positions are (ICRS) at Ep=2016.0 for Gaia sources,
and J2000 for sources with only 2MASS magnitudes.
Note (2): how the effective temperature was calculated as follows:
S = Spectroscopically determined from fit to spectral features
T = Tau, temperature determined from measured spectral index Tau
GK = G-K colour, temperature inferred from dereddened G-K
GH = G-H colour, temperature inferred from dereddened G-H
BPRP = BP-RP colour, temperature inferred from dereddened BP-RP
JK = J-K colour, temperature inferred from dereddened J-K
GJ = G-J colour, temperature inferred from dereddened G-J
GRP = G-RP colour, temperature inferred from dereddened G-RP
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Acknowledgements:
Nicholas J. Wright, n.j.wright(at)keele.ac.uk
(End) Nicholas Wright [Keele, UK], Patricia Vannier [CDS] 06-Dec-2024