J/A+A/597/A22 Massive O- and B-type stars velocities (Simon-Diaz+, 2017)
The IACOB project.
III. New observational clues to understand macroturbulent broadening in
massive O- and B-type stars.
Simon-Diaz S., Godart M., Castro N., Herrero A., Aerts C., Puls J.,
Telting J., Grassitelli L.
<Astron. Astrophys. 597, A22 (2017)>
=2017A&A...597A..22S 2017A&A...597A..22S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type; Rotational velocities; Equivalent widths
Keywords: stars: early-type - stars: fundamental parameters - stars: massive -
stars: rotation - stars: oscillations - techniques: spectroscopic
Abstract:
The term macroturbulent broadening is commonly used to refer to a
certain type of non-rotational broadening acting the spectral line
profiles of O- and B-type stars. It has been proposed to be a
spectroscopic signature of the presence of stellar oscillations;
however, we still lack a definitive confirmation of this hypothesis.
We aim to provide new empirical clues about macroturbulent spectral
line broadening in O- and B-type stars to evaluate its physical
origin.
We used high-resolution spectra of 430 stars with spectral types in
the range O4-B9 (all luminosity classes) compiled in the framework
of the IACOB project. We characterized the line broadening of adequate
diagnostic metal lines using a combined Fourier transform and
goodness-of-fit technique. We performed a quantitative spectroscopic
analysis of the whole sample using automatic tools coupled with a huge
grid of FASTWIND models to determine their effective temperatures and
gravities. We also incorporated quantitative information about line
asymmetries into our observational description of the characteristics
of the line profiles, and performed a comparison of the shape and type
of line-profile variability found in a small sample of O stars and B
supergiants with still undefined pulsational properties and B
main-sequence stars with variable line profiles owing to a
well-identified type of stellar oscillations or to the presence of
spots in the stellar surface.
Description:
The main observational sample discussed in this paper comprises
high-resolution, single snapshot spectra of 431 O- and B-type Galactic
stars.
The IACOB database includes spectra from two different instruments:
the FIES and HERMES spectrographs attached to the 2.56m Nordic Optical
Telescope and the 1.2m Mercator telescope, respectively. Both
instruments provide a complete wavelength coverage between 3800 and
7000Å (9000Å for the case of HERMES spectra), and the associated
resolving power (R) of the spectra is 25000, 46000 (FIES) and 85000
(HERMES). By default, all the spectra in the IACOB database are
reduced using the corresponding available pipelines (FIEStool and
HermesDRS, respectively) and they are normalized by means of our own
procedures implemented in IDL.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 80 431 List of stars considered for this paper
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See also:
J/A+A/562/A135 : Northern Galactic OB stars vsini (Simon-Diaz+, 2014)
J/A+A/597/A22 : Massive O- and B-type stars velocities (Simon-Diaz+, 2017)
J/A+A/613/A65 : Spectroscopic parameters of O-type stars (Holgado+, 2018)
J/A+A/613/A9 : Extinction towards Galactic O stars (Maiz Apellaniz+, 2018)
J/A+A/639/A157 : Massive O-type stars near ZAMS elusive detection
(Holgado+, 2020)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Target HD number of the star
15- 31 A17 --- SpType Spectral type (1)
33- 37 A5 --- Line Line used to determine the line-broadening
parameters
40- 42 I3 --- S/Nc Signal-to-noise ratio of the adjacent continuum
44- 46 I3 0.1pm EW Equivalent width of the line
48- 50 I3 km/s vsiniF Projected rotational velocity as derived from
the Fourier transform (FT) approach
52- 54 I3 km/s vsiniG Projected rotational velocity as derived from
the goodness of fit (GOF) approach
56 A1 --- l_vmac Limit flag on vmac
57- 59 I3 km/s vmac Macroturbulent velocity as derived from the
goodness of fit (GOF) approach
61- 65 F5.2 --- RSk Relative skewness of the line profile as
derived using Eq. 1 in the paper (2)
67- 70 F4.2 --- e_RSk rms uncertainty on RSk
72- 75 F4.2 [K] logTeff ?=- Effective temperature
77- 80 F4.2 [Lsun] logL ?=- Luminosity (L=Teff4/g)
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Note (1): Spectral classifications must be handled with caution since they come
from various sources, not all of which are equally reliable.
Note (2): Relative skewness, RSk=<v3>/(<v2>3/2), where v2 and v3 are
the second and third normalized central moments of a spectral line,
see Equation (1), Sect. 3.2 of the paper.
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History:
From electronic version of the journal
References:
Simon-Diaz et al., Paper I 2014A&A...562A.135S 2014A&A...562A.135S, Cat. J/A+A/562/A135
Simon-Diaz et al., Paper II 2014A&A...570L...6S 2014A&A...570L...6S
Simon-Diaz et al., Paper III 2017A&A...597A..22S 2017A&A...597A..22S, Cat, J/A+A/597/A22
Godart et al., Paper IV 2017A&A...597A..23G 2017A&A...597A..23G
Holgado et al., Paper V 2018A&A...613A..65H 2018A&A...613A..65H, Cat. J/A+A/613/A65
Maiz-Apellaniz & Barba, 2018A&A...613A...9M 2018A&A...613A...9M, Cat. J/A+A/613/A9
Holgado et al. Paper VI 2020A&A...639A.157H 2020A&A...639A.157H, Cat. J/A+A/639/A157
(End) Patricia Vannier [CDS] 09-Dec-2016