J/AJ/150/41 Rotational velocities of 136 B stars from ALS (Garmany+, 2015)
Projected rotational velocities of 136 early B-type stars in the outer galactic
disk.
Garmany C.D., Glaspey J.W., Braganca G.A., Daflon S., Borges Fernandes M.,
Oey M.S., Bensby T., Cunha K.
<Astron. J., 150, 41 (2015)>
=2015AJ....150...41G 2015AJ....150...41G
ADC_Keywords: Clusters, open ; Stars, early-type ; Stars, Be ; Spectral types ;
Rotational velocities ; Radial velocities
Keywords: open clusters and associations: general - stars: early-type -
stars: emission-line, Be - stars: rotation
Abstract:
We have determined projected rotational velocities, vsini, from
Magellan/MIKE echelle spectra for a sample of 136 early B-type stars
having large Galactocentric distances. The target selection was done
independently of their possible membership in clusters, associations
or field stars. We subsequently examined the literature and assigned
each star as Field, Association, or Cluster. Our vsini results are
consistent with a difference in aggregate vsini with stellar density.
We fit bimodal Maxwellian distributions to the Field, Association, and
Cluster subsamples representing sharp-lined and broad-lined
components. The first two distributions, in particular, for the Field
and Association are consistent with strong bimodality in vsini. Radial
velocities are also presented, which are useful for further studies of
binarity in B-type stars, and we also identify a sample of possible
new double-lined spectroscopic binaries. In addition, we find 18
candidate Be stars showing emission at Hα.
Description:
Our sample of early B-type stars is designed to select targets with
the greatest possible galactocentric distances. We used the
compilation by Reed (see Reed 2005, cat. V/125) of the Case-Hamburg
survey. We selected stars in the Reed catalog between galactic
longitudes of 180°-250°.
High-resolution spectra were obtained over six beautiful nights (2007
December 29-2008 January 3) with the MIKE spectrograph at the Magellan
Clay 6.5m telescope at Las Campanas Observatory in Chile. MIKE is a
double echelle spectrograph that simultaneously records red
(4900-9500Å) and blue (3350-5000Å) spectra. Using a 0.7'' slit,
we obtained a spectral resolution in the blue of about 53000,
calculated from measurements of the Th-Ar calibration images, which
indicated 1.9 pixels as the best Full Width at Half Maximum (FWHM)
along the dispersion direction with 0.041Å/pixel.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 124 136 Observed and derived data
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See also:
V/125 : Photometry and Spectroscopy for Luminous Stars (Reed 2005)
III/244 : Catalog of Stellar Rotational Velocities (Glebocki+ 2005)
J/AJ/144/130 : Rotational velocities of nearby HIP B stars (Braganca+, 2012)
J/ApJ/722/605 : A stellar rotation census of B stars (Huang+, 2010)
J/AJ/134/1570 : Rotational velocities of OB stars (Daflon+, 2007)
J/ApJ/648/580 : Rotational velocities in 19 open clusters (Huang+, 2006)
J/ApJ/573/359 : Rotational velocities of B stars from BSC (Abt+, 2002)
J/AJ/98/1305 : Stellar content of NGC 346 (Massey+, 1989)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ALS [7/19267] Number in the ALS (Alma Luminous
Stars) catalog (Reed 2003, cat. V/125)
7- 11 F5.2 mag Vmag [10/14.7] Apparent V mag (Reed 2003, cat. V/125)
13- 16 F4.2 0.1nm W4026 [0.9/6.12]? The HeIλ4026 Full Width at
Half Maximum (FWHM) (in Å)
18- 21 F4.2 0.1nm W4387 [0.81/8.76]? The HeIλ4388 Full Width
at Half Maximum (FWHM) (in Å)
23- 26 F4.2 0.1nm W4471 [0.8/7.68]? The HeIλ4471 Full Width at
Half Maximum (FWHM) (in Å)
28- 30 I3 km/s vsini [0/310]? Mean HeI derived rotational velocity
vsin(i)
32- 33 I2 km/s e_vsini [0/59]? Uncertainty in
35- 39 F5.1 km/s RV [-14/128]? Radial velocity
41- 44 F4.1 km/s e_RV [1.5/75]? Standard deviation for RV
46- 47 I2 --- o_RV [4/10]? Number of lines measured
49- 53 F5.2 mag Q [-1/-0.6] Q=(U-B)-0.72(B-V) reddening free index
55- 58 F4.2 mag E(B-V) [0.19/1.2] The E(B-V) color excess (1)
60- 63 F4.1 mag VMag [-6/-2.1] Absolute V-band magnitude (2)
65- 68 F4.1 kpc Dist [1/13.1] Photometrically derived heliocentric
distance
70- 83 A14 --- SpT Spectral type (from Reed 2003, cat. V/125)
85 A1 --- Cl [CAF] Membership classification: (C)luster,
(A)ssociation, or (F)ield (as described in
Section 3.1)
87- 95 A9 --- SB Binarity (SB1/2) (3)
97-107 A11 --- Ha Hα emission
109-112 A4 --- Ref Reference (3)
114-124 A11 --- Mm Membership in an association or cluster
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Note (1): From Massey et al 1989 (J/AJ/98/1305); (B-V)0=0.33Q-0.017.
Note (2): VMag=0.66+1.59Q-4.79Q2 (Equation (1) in the paper).
Note (3): The reference codes are:
D07 = A subset of eight stars included in this study were previously observed
in a study of v sin i by Daflon et al. 2007 (cat. J/AJ/134/1570);
HG06 = Six of our stars were observed by Huang & Gies 2006 (J/ApJ/648/580),
who derived v.sin(i) values.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 02-Oct-2015