J/AJ/134/1570 Rotational velocities of OB stars (Daflon+, 2007)
The projected rotational velocity distribution of a sample of OB stars from a
calibration based on synthetic He I lines.
Daflon S., Cunha K., De Araujo F.X., Wolff S., Przybilla N.
<Astron. J., 134, 1570-1578 (2007)>
=2007AJ....134.1570D 2007AJ....134.1570D
ADC_Keywords: Associations, stellar ; Stars, OB ; Rotational velocities
Keywords: line: profiles - stars: early-type - stars: rotation
Abstract:
We derive projected rotational velocities (vsini) for a sample of
156 Galactic OB star members of 35 clusters, HII regions, and
associations. The HeI lines at 4026, 4388, and 4471Å were analyzed
in order to define a calibration of the synthetic HeI full widths at
half-maximum (FWHMs) versus stellar vsini. A grid of synthetic
spectra of HeI line profiles was calculated in non-LTE using an
extensive helium model atom and updated atomic data. The vsini
values for all stars were derived using the HeI FWHM calibrations,
but also, for those target stars with relatively sharp lines, vsini
values were obtained from best-fit synthetic spectra of up to 40 lines
of CII, NII, OII, AlIII, MgII, SiIII, and SIII. This calibration is a
useful and efficient tool for estimating the projected rotational
velocities of O9-B5 main-sequence stars. The distribution of vsini for
an unbiased sample of early B stars in the unbound association Cep OB2
is consistent with the distribution reported elsewhere for other
unbound associations.
Description:
The observational data for this study are high-resolution spectra of
late O and early B type stars that were obtained during several
observing runs between the years 1994 and 2000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 156 vsin(i) Results
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See also:
J/MNRAS/284/265 : Rotational velocities of 373 OB stars (Howarth+ 1997)
J/A+A/457/265 : The VLT-FLAMES survey of massive stars (Dufton+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- CName Cluster name
11- 26 A16 --- SName Star name
28- 29 A2 --- n_SName Remark on binarity (1)
31- 35 I5 K Teff Effective temperature
36 A1 --- u_Teff Uncertainty flag on Teff
37 A1 --- f_Teff [1]? Assumed Teff=30000K to calculate vsin(i)
39- 41 I3 km/s ? Mean vsin(i) velocity from weak metal lines
43- 44 I2 km/s e_ ? Uncertainty in <vsiniM>
46- 48 F3.1 --- W4026 ? The He I (4026) FWHM
49 A1 --- u_W4026 ? Uncertainty flag on W4026
51- 53 I3 km/s vsini4026 ? The He I (4026) vsin(i)
55- 57 F3.1 --- W4387 ? The He I (4387) FWHM
58 A1 --- u_W4387 ? Uncertainty flag on W4387
60- 62 I3 km/s vsini4387 ? The He I (4387) vsin(i)
64- 66 F3.1 --- W4471 ? The He I (4471) FWHM
67 A1 --- u_W4471 ? Uncertainty flag on W4471
69- 71 I3 km/s vsini4471 ? The He I (4477) vsin(i)
73- 75 I3 km/s <vsiniHe> Mean He I derived vsin(i)
77- 78 I2 km/s e_<vsiniHe> ? Uncertainty in <vsiniHe>
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Note (1): Flag as follows:
dg = Asymmetric line profiles: possible spectroscopic binary?
dd = Single-lined spectroscopic binary (SB1)
* = Double-lined spectroscopic binary (SB2)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 11-Nov-2009