J/A+A/331/81 Hyades membership (Perryman+ 1998)
The Hyades: distance, structure, dynamics, and age
Perryman M.A.C., Brown A.G.A., Lebreton Y., Gomez A., Turon C.,
Cayrel de Strobel G., Mermilliod J.C., Robichon N., Kovalevsky J.,
Crifo F.
<Astron. Astrophys. 331, 81 (1998)>
=1998A&A...331...81P 1998A&A...331...81P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Radial velocities ; Stars, distances ;
Parallaxes, trigonometric
Keywords: astrometry - parallaxes - HR Diagram - Hyades - distance scale
Abstract:
We use absolute trigonometric parallaxes from the Hipparcos Catalogue
(Cat. I/239) to determine individual distances to members of the
Hyades cluster, from which the 3-dimensional structure of the cluster
can be derived. Inertially-referenced proper motions are used to
rediscuss distance determinations based on convergent-point analyses.
A combination of parallaxes and proper motions from Hipparcos, and
radial velocities from ground-based observations, are used to
determine the position and velocity components of candidate members
with respect to the cluster centre, providing new information on
cluster membership: 13 new candidate members within 20pc of the
cluster centre have been identified. Farther from the cluster centre
there is a gradual merging between certain cluster members and field
stars, both spatially and kinematically. Within the cluster, the
kinematical structure is fully consistent with parallel space motion
of the component stars with an internal velocity dispersion of about
0.3km/s. The spatial structure and mass segregation are consistent
with N-body simulation results, without the need to invoke expansion,
contraction, rotation, or other significant perturbations of the
cluster. The quality of the individual distance determinations permits
the cluster zero-age main sequence to be accurately modelled. The
helium abundance for the cluster is determined to be Y=0.26±0.02
which, combined with isochrone modelling including convective
overshooting, yields a cluster age of 625±50Myr. The distance to the
observed centre of mass (a concept meaningful only in the restricted
context of the cluster members contained in the Hipparcos Catalogue)
is 46.34±0.27pc, corresponding to a distance modulus
m-M=3.33±0.01mag for the objects within 10pc of the cluster centre
(roughly corresponding to the tidal radius). This distance modulus is
close to, but significantly better determined than, that derived from
recent high-precision radial velocity studies, somewhat larger than
that indicated by recent ground-based trigonometric parallax
determinations, and smaller than those found from recent studies of
the cluster convergent point. These discrepancies are investigated and
explained.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 107 282 Data on the membership of the Hyades for the
282 stars in the sample of Perryman et al.
--------------------------------------------------------------------------------
See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- HIP Hipparcos Catalogue (HIP, Cat. I/239) number
7- 9 I3 --- vB ? van Bueren number (1952BAN....11..385V 1952BAN....11..385V)
10 A1 --- n_vB [n] n: new candidate proposed in this paper
12 I1 --- MembvB [0/1]? Membership according to van Bueren (1)
14- 16 I3 --- vA ? van Altena number (1969AJ.....74....2V 1969AJ.....74....2V)
17 A1 --- n_vA [n] n: new candidate proposed in this paper
19 I1 --- MembvA [0/1]? Membership according to van Altena (1)
21- 23 I3 --- Han ? Hanson number (1975, Cat. J/AJ/80/379)
24 A1 --- n_Han [n] n: new candidate proposed in this paper
26 I1 --- MembHan [0/1]? Membership according to Hanson (1)
28- 31 I4 --- Pel ? Pels et al. (1975A&A....43..423P 1975A&A....43..423P) (Leiden)
number, van Bueren stars have the
vB number + 1000
32 A1 --- n_Pel [n] n: new candidate proposed in this paper
34 I1 --- MembPel [0/1]? Membership according to Pels et al. (1)
36- 38 I3 --- Grif ? Sequential number in Table4 of
Griffin et al. (1988AJ.....96..172G 1988AJ.....96..172G)
39 A1 --- n_Grif [n] n: new candidate proposed in this paper
41 I1 --- MembGrif [0/1]? Membership according to Griffin et al. (1)
43- 45 I3 --- Scha ? Schwan number (1991A&A...243..386S 1991A&A...243..386S)
46 A1 --- n_Scha [n] n: new candidate proposed in this paper
48 I1 --- MembScha [0/1]? Membership according to Schwan (1)
50- 56 F7.2 mas plx Hipparcos parallax (milliarcsec=mas)
58- 63 F6.2 mas e_plx Hipparcos parallax standard error
65- 71 F7.2 km/s RV ? Radial velocity
72 A1 --- u_RV [?] Uncertainty flag on RV
73 A1 --- n_RV [#] # indicates SB/RV with undetermined gamma
velocity
74- 77 F4.2 km/s e_RV ? Error in radial velocity
80- 81 I2 --- r_RV ? Source of radial velocity (2)
83- 84 A2 --- Note [SB RV] SB: spectroscopic binary,
RV: radial velocity (possibly) variable
86 A1 --- Note2 [HIM] Historical status flag (3)
88- 90 A3 --- Note3 [CGOVX S/] Double/Multiple Systems flag (4)
92- 97 F6.1 pc Dist Distance from the cluster centre defined by
the 134 stars within r<10 pc (see Table 3)
99-105 F7.2 --- Stat Kinematic statistic (5)
107 A1 --- Memb [0/1?] Final membership assigned in this paper
`?' indicates possible new members
unclassifiable due to unknown radial velocities
--------------------------------------------------------------------------------
Note (1): Data on the membership of the Hyades for the 282 stars in our sample,
listed by various authors. Membership or non-membership inferred by
the relevant authors are indicated by `1' or `0' in the corresponding
column respectively (see paper for details).
Note (2): Sources of radial velocities:
(0) Radial velocity unknown;
(1) Griffin et al., 1988AJ.....96..172G 1988AJ.....96..172G
1985AJ.....90..609G 1985AJ.....90..609G
1981AJ.....86..588G 1981AJ.....86..588G
1978AJ.....83.1114G 1978AJ.....83.1114G
1977AJ.....82..176G 1977AJ.....82..176G
1982A&A...106..221G 1982A&A...106..221G
(2) Hipparcos Input Catalogue, Cat. I/196 (mainly from
R.E. Wilson, 1953, Cat. III/21)
(3) Weighted mean of ref. 2 (39.6±1.2) and
Kraft, 1965ApJ...142..681K 1965ApJ...142..681K (38.4±1.5)
(4) Kraft, 1965ApJ...142..681K 1965ApJ...142..681K (37.4±0.4 and 36.5±0.5)
Cheriguene, 1971A&A....13..447C 1971A&A....13..447C (37.3±0.7)
(5) McClure, 1982ApJ...254..606M 1982ApJ...254..606M
(6) Torres et al., 1997ApJ...474..256T 1997ApJ...474..256T
(7) Mayor & Mazeh, 1987A&A...171..157M 1987A&A...171..157M
(8) Kraft, 1965ApJ...142..681K 1965ApJ...142..681K
(9) Margoni et al., 1992A&AS...93..545M 1992A&AS...93..545M
(10) Lucy & Sweeney, 1971AJ.....76..544L 1971AJ.....76..544L
(11) Abt & Levy, 1985ApJS...59..229A 1985ApJS...59..229A
(12) Griffin, 1971MNRAS.155....1G 1971MNRAS.155....1G
(13) Andersen & Nordstrom, 1983A&A...122...23A 1983A&A...122...23A
(14) Morse et al., 1991AJ....101.1495M 1991AJ....101.1495M
(15) Detweiler et al., 1984AJ.....89.1038D 1984AJ.....89.1038D
(16) Weighted mean of data from Palmer et al., 1968RGOB..135..385P 1968RGOB..135..385P
and Stillwell, 1948PDAO....7..337S 1948PDAO....7..337S
(17) Tomkin et al., 1995AJ....109..780T 1995AJ....109..780T
(18) Heintz, 1981ApJS...46..247H 1981ApJS...46..247H
(19) Abt, 1965ApJS...11..429A 1965ApJS...11..429A
(20) Fekel, 1980PASP...92..785F 1980PASP...92..785F
(21) Perraud, 1962JO.....45..361P 1962JO.....45..361P
(22) Fouts & Sandage, 1986AJ.....91.1189F 1986AJ.....91.1189F, Cat. III/144 (star G83-18)
(23) Strassmeier et al., 1988A&AS...72..291S 1988A&AS...72..291S, See Cat. V/76
(24) New Coravel observations provided by J.C. Mermilliod
(25) Woolley et al., 1971ROAn...14....1W 1971ROAn...14....1W
(26) Hanson & Vasilevskis, 1983AJ.....88..844H 1983AJ.....88..844H
(27) Evans, 1978BICDS..15..121E 1978BICDS..15..121E
(28) Orbit recomputed by Mermilliod with period=490±1d (from Batten)
Note (3): Star was previously known, or classified by Hipparcos, to have
resolved components (from Field H56, Cat. I/239); this may overlap
with the flag in the next column, but may also indicate visual
or wide binary (see paper for details)
H : determined multiple by Hipparcos, previously unknown
I : system previously identified as multiple in HIC I/196 (annex1)
M : miscellaneous (system identified after publication of HIC)
Note (4): C, G, O, V, or X = relevant part of the Hipparcos Double and Multiple
Systems Annex, from Field H59 (Cat. I/239),
C: solutions for the components
G: acceleration or higher order terms
O: orbital solutions
V: variability-induced movers (apparent motion arises from variability)
X: stochastic solution (probably astrometric binaries with short period)
supplemented by S = suspected binary in Hipparcos Catalogue, from Field H61,
Cat. I/239, (see paper for details)
Note (5): A value of 14.16 corresponding to 3σ, see paper for details.
--------------------------------------------------------------------------------
Acknowledgements: Anthony Brown
(End) Patricia Bauer [CDS] 24-Jul-1997