J/MNRAS/477/3197 Radial velocities of Hyades members (Reino+, 2018)
A Gaia study of the Hyades open cluster.
Reino S., De Bruijne J., Zari E., D'Antona F., Ventura P.
<Mon. Not. R. Astron. Soc., 477, 3197-3216 (2018)>
=2018MNRAS.477.3197R 2018MNRAS.477.3197R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Radial velocities
Keywords: astrometry - stars: distances - stars: fundamental parameters -
open clusters and associations: individual: Hyades
Abstract:
We present a study of the membership of the Hyades open cluster,
derive kinematically modelled parallaxes of its members, and study the
colour-absolute magnitude diagram of the cluster. We use Gaia DR1
Tycho-Gaia Astrometric Solution (TGAS) data complemented by
Hipparcos-2 data for bright stars not contained in TGAS. We supplement
the astrometric data with radial velocities collected from a dozen
literature sources. By assuming that all cluster members move with the
mean cluster velocity to within the velocity dispersion, we use the
observed and the expected motions of the stars to determine individual
cluster membership probabilities. We subsequently derive improved
parallaxes through maximum-likelihood kinematic modelling of the
cluster. This method has an iterative component to deal with
'outliers', caused for instance by double stars or escaping members.
Our method extends an existing method and supports the mixed presence
of stars with and without radial velocities. We find 251 candidate
members, 200 of which have a literature radial velocity, and 70 of
which are new candidate members with TGAS astrometry. The cluster is
roughly spherical in its centre but significantly flattened at larger
radii. The observed colour-absolute magnitude diagram shows a clear
binary sequence. The kinematically modelled parallaxes that we derive
are a factor ∼1.7/2.9 more precise than the TGAS/ Hipparcos-2
values and allow us to derive an extremely sharp main sequence. This
sequence shows evidence for fine-detailed structure that is elegantly
explained by the full spectrum turbulence model of convection.
Description:
We study the Hyades open cluster using Gaia DR1 astrometry
complemented by Hipparcos-2 astrometry for bright stars and by
literature radial velocities from 12 sources.
If an object has radial velocity matches in several source catalogues,
we use the following priority ranking: Perryman et al. (1998, Cat.
J/A+A/331/81), Griffin (2012JApA...33...29G 2012JApA...33...29G), Griffin
(2013Obs...133..144G 2013Obs...133..144G), Mermilliod et al. (2009, Cat. J/A+A/331/81),
White et al. (2007, Cat. J/AJ/133/2524), Tabernero et al. (2012, Cat.
J/A+A/547/A13), Debernardi et al. (2000, Cat. J/A+A/354/881), HADES,
XHIP, RAVE, APOGEE, and GALAH. This allows us to construct a final
table in which each star is assigned a single radial velocity (or a
null value in case no radial velocity measurement exists) plus an
identifying number to track the associated literature source. In
total, there are 228 radial velocities from Perryman et al. (1998,
Cat. J/A+A/331/81), 5 from Griffin (2012JApA...33...29G 2012JApA...33...29G), 10 from
Griffin (2013Obs...133..144G 2013Obs...133..144G), 12 from Mermilliod et al. (2009, Cat.
J/A+A/331/81), 19 from White et al. (2007, Cat. J/AJ/133/2524), 3 from
Tabernero et al. (2012, Cat. J/A+A/547/A13), 0 from Debernardi et al.
(2000, Cat. J/A+A/354/881), 4 from HADES, 591 from XHIP, 23 from RAVE,
12 from APOGEE, and 1 from GALAH.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 82 251 Radial velocities of Hyades members
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- HIP ?=- Hipparcos identifier
7- 17 A11 --- TYC Tycho-2 identifier
19- 37 I19 --- GaiaDR1 ?=- Gaia DR1 identifier (source_id)
39- 46 F8.5 --- c c-value (chi-squared) of the star
48- 53 F6.4 --- p p-value of the star corresponding to
the c-value
55- 60 F6.3 km/s RV ?=- Radial velocity (in km/s)
62- 66 F5.3 km/s e_RV ?=- Radial velocity error (which have been
inflated due to the zero-point differences)
68- 69 I2 --- r_RV ?=- Source of the radial velocity
measurement (1)
71- 76 F6.3 mas plxmod ?=- Kinematically modelled parallax for this
star (if missing then the star was rejected
during kinematic modelling)
78- 82 F5.3 mas e_plxmod ?=- Standard deviation of the modelled parallax
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Note (1): Source of the radial velocity measurement as follows:
1 = XHIP (Anderson et al., 2012, 2012AstL...38..331A 2012AstL...38..331A, Cat. V/137)
2 = RAVE
3 = APOGEE
4 = GALAH
5 = Perryman et al. (1998A&A...331...81P 1998A&A...331...81P, Cat. J/A+A/331/81)
6 = HADES
7 = White et al. (2007AJ....133.2524W 2007AJ....133.2524W, Cat. J/AJ/133/2524)
8 = Mermilliod et al. (2009A&A...498..949M 2009A&A...498..949M, Cat. J/A+A/498/949)
9 = Tabernero et al. (2012A&A...547A..13T 2012A&A...547A..13T, Cat. J/A+A/547/A13)
10 = Griffin (2012JApA...33...29G 2012JApA...33...29G)
11 = Griffin (2013Obs...133..144G 2013Obs...133..144G )
12 = Debernardi et al. (2000A&A...354..881D 2000A&A...354..881D, Cat. J/A+A/354/881)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Jun-2021