J/A+A/354/881 Radial velocities of Praesepe & Hyades Am stars (Debernardi+ 2000)
Binarity of Am stars in Praesepe and Hyades
Debernardi Y., Mermilliod J.-C., Carquillat J.-M., Ginestet N.
<Astron. Astrophys. 354, 881 (2000)>
=2000A&A...354..881D 2000A&A...354..881D
ADC_Keywords: Clusters, open ; Binaries, spectroscopic ; Stars, Am ;
Radial velocities
Keywords: Galaxy: open clusters and associations: individual: Praesepe -
Galaxy: open clusters and associations: individual: Hyades -
stars: chemically peculiar - stars: binaries: spectroscopic
Abstract:
CORAVEL radial-velocity observations of Am stars in the Hyades and
Praesepe have allowed the determination of orbital elements for 10
spectroscopic binaries, among which 3 are first determinations. One Am
star (KW 40) is found to be a well hierarchised triple system. KW 538
has a rather long period (435 days) for an Am star. Orbits of systems
with periods shorter than 8.5 days are circularized, or present
eccentricities smaller than 0.04. For 19 Am stars, the number of
quadruple-, triple-, double-, single systems is 1:2:14(10+4?):(2?).
The Am stars in a (β, B-V) diagram clearly stand away by 0.03mag
from the sequence defined by normal main-sequence stars. This diagram
could be a powerful method to identify Am stars in more distant open
clusters, provided there is no differential reddening. In the
colour-magnitude diagram (MV, β), double-lined binaries are
0.6-0.7mag above the ZAMS as expected, while most single-lined are
close to or on the ZAMS because the secondary does not contribute much
light. The absence of X-ray detection of 4 systems in the Hyades is an
argument for the presence of a white dwarf secondary.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 74 10 List of stars (from table 1)
table2.dat 56 401 Individual radial velocities
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Star name
11- 12 I2 h RAh Right Ascension J2000 (hours)
14- 15 I2 min RAm Right Ascension J2000 (minutes)
17- 20 F4.1 s RAs Right Ascension J2000 (seconds)
22 A1 --- DE- Declination J2000 (sign)
23- 24 I2 deg DEd Declination J2000 (degrees)
26- 27 I2 arcmin DEm Declination J2000 (minutes)
29- 30 I2 arcsec DEs Declination J2000 (seconds)
33- 37 F5.3 mag Vmag Johnson blue magnitude
40- 44 F5.3 mag B-V Johnson color index
46- 53 A8 --- SpType MK spectral type
55- 63 F9.5 d Period Period
66- 74 A9 --- Remark Remark about duplicity
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Henry Draper Catalog (Cat. III/135) number
10- 11 I2 h RAh Right ascension, J2000
13- 14 I2 min RAm Right ascension, J2000
16- 19 F4.1 s RAs Right ascension, J2000
21 A1 --- DE- Declination sign
22- 23 I2 deg DEd Declination, J2000
25- 26 I2 arcmin DEm Declination, J2000
28- 29 I2 arcsec DEs Declination, J2000
31- 41 F11.3 d HJD Heliocentric Julian Date
43- 48 F6.2 km/s RV Barycentric radial velocity
51- 54 F4.2 km/s e_RV Internal estimate of velocity error
56 A1 --- Comp Component of the binary system
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Acknowledgements: Yves Debernardi
(End) Patricia Bauer [CDS] 09-Mar-2000