J/A+A/315/384 Binarity among B-stars in NGC 6231 (Raboud, 1996)
Binarity among B-stars in NGC 6231
Raboud D.
<Astron. Astrophys. 315, 384 (1996)>
=1996A&A...315..384R 1996A&A...315..384R (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: cluster: open: individual: NGC 6231 - technique: radial velocities -
binary: general; spectroscopic
Description:
We have measured radial velocities for 53 B-type stars, between B1 and
B9, in the young open cluster NGC 6231 through a cross-correlation
technique with synthetic spectra. Two measurements for 36 stars of the
sample were obtained with a time separation of about two years. We
derived a minimum binary fraction of 52% in the considered
population. The velocity determination precisions were simulated and
we analysed their dependence upon the S/N ratios of the spectra and
upon the stellar rotational velocities. We discuss the selection of
the templates for the correlation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3 144 97 Results for all programme stars
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Byte-by-byte Description of file: table3
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Bytes Format Units Label Explanations
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1- 4 I4 --- Number []? Star number from Seggewiss
(1968VeBon..79....1S 1968VeBon..79....1S)
13- 18 F6.3 mag Vmag []? V magnitude
24- 28 F5.3 mag [B-V] []? Color index
34- 38 I5 K Teff []? Effective temperature calculated (1)
40- 42 A3 --- n_Teff Remark on Teff determination (2)
47- 49 I3 km/s Vsini []? Rough determination of Vsini (3)
56- 58 A3 --- r_Teff Source of the photometry and Teff (4)
71- 81 F11.3 --- JD Julian Date of the observation
90- 94 F5.1 km/s RV []? Radial velocities
97-100 A4 --- n_RV SBII characteristic of the star (5)
103-105 F3.1 km/s e_RV []? Radial velocity uncertainties (6)
113-117 F5.1 km/s RVdiff1 []? Radial velocity differences (7)
120-123 F4.1 km/s RVdiff2 []? Radial velocity differences (7)
129-133 F5.1 km/s RVdiff3 []? Radial velocity differences (8)
136-139 F4.1 km/s RVdiff4 []? Radial velocity differences (8)
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Note (1): See Sect. 3.2.1 of the paper.
Note (2): The question mark in brackets indicates that the determination is
possibly outside the validity range of the Q parameter (see Sect. 3.2.1).
Note (3): See Sect. 3.2.2.
Note (4): GE is for the Geneva photometry, pe for UBV photoelectric and pg for
UBV photographic photometry. The digits have the following significations:
1 = Teff from Spectral Type estimated from equivalent widths
(Didelon 1982A&AS...50..199D 1982A&AS...50..199D)
2 = V and [B-V] from Garrison & Schild (1979AJ.....84.1020G 1979AJ.....84.1020G),
Teff from Van Genderen et al. (1984A&AS...58..537V 1984A&AS...58..537V)
3 = Seggewiss (1968VeBon..79....1S 1968VeBon..79....1S)
4 = V and [B-V] from Seggewiss (1968VeBon..79....1S 1968VeBon..79....1S), Teff calculated from
uvby photometry (Shobbrook 1983MNRAS.205.1229S 1983MNRAS.205.1229S)
5 = Garrison & Schild (1979AJ.....84.1020G 1979AJ.....84.1020G)
6 = V and [B-V] from Garrison & Schild (1979AJ.....84.1020G 1979AJ.....84.1020G),
Teff calculated from uvby photometry (Shobbrook 1983MNRAS.205.1229S 1983MNRAS.205.1229S)
7 = V and [B-V] from Geneva photometry,
Teff from Spectral Type (Kilian et al. 1994A&A...284..437K 1994A&A...284..437K) and
Vsini from Kilian et al. (1994A&A...284..437K 1994A&A...284..437K)
8 = V and [B-V] from Garrison & Schild (1979AJ.....84.1020G 1979AJ.....84.1020G),
Teff from Spectral Type (Garrison & Schild 1979AJ.....84.1020G 1979AJ.....84.1020G)
9 = Heske & Wendker (1984A&AS...57..205H 1984A&AS...57..205H)
Note (5): See Sect. 6.1.4.
Note (6): Radial velocity uncertainties, obtained from the simulations
described in Sect. 4, using a fixed B1 synthetic spectrum for all cases,
and adapted in order to reproduce exactly the conditions of the radial
velocity determinations for the two runs (i.e. without the region between
430 nm and 440 nm, see Sect. 3.3).
Note (7): Differences between radial velocities of column RV.
Note (8): Differential radial velocities obtained without any template
(see text).
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Acknowledgements: Didier Raboud
(End) Raboud [University of Lausanne], Patricia Bauer [CDS] 14-May-1996