J/A+A/687/A228 527 luminous blue stars spectroscopic analysis (de Burgos+, 2024)
The IACOB project. X. Large-scale quantitative spectroscopic analysis of
Galactic luminous blue stars.
de Burgos A., Simon-Diaz S., Urbaneja M.A., Puls J.
<Astron. Astrophys. 687, A228 (2024)>
=2024A&A...687A.228D 2024A&A...687A.228D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, OB; Spectroscopy ; HR diagrams ; Abundances ; Models
Keywords: techniques: spectroscopic - stars: abundances - stars: evolution -
stars: fundamental parameters - stars: massive - supergiants
Abstract:
Blue supergiants (BSGs) are key objects for understanding the
evolution of massive stars. However, discrepancies between theoretical
predictions and empirical observations have opened up important
questions yet to be answered. Studying statistically significant and
unbiased samples of BSGs can help to improve the situation. We aim to
perform a homogeneous and comprehensive quantitative spectroscopic
analysis of a large sample of Galactic luminous blue stars (a majority
of which are BSGs) from the IACOB spectroscopic database. We derive
the projected rotational velocity (vsin(i)) and the macroturbulent
broadening (vmac) using IACOB-BROAD. We used FASTWIND computations to
derive effective temperatures (Teff), surface gravities,
microturbulences (xi), silicon and helium surface abundances, and the
wind-strength parameter. We provide estimates of these quantities for
the largest sample of Galactic luminous O9-B5 stars spectroscopically
analyzed to date, comprising 527 targets. We find a drop in the
relative number of stars at ∼21 kK, coinciding with a scarcity of fast
rotating stars below that temperature. We speculate that this feature
might be roughly delineating the location of the
Terminal-Age-Main-Sequence in the 15-85M_sol range. By investigating
the main characteristics of the vsin(i) distribution as a function of
Teff, we propose that an efficient mechanism transporting angular
momentum from the stellar core to the surface might be operating along
the main sequence. We find correlations between xi, v_mac and the
spectroscopic luminosity. We also find that no more than 20% of the
stars in our sample have atmospheres clearly enriched in helium, and
suggest that the origin of this specific sub-sample might be in binary
evolution. We do not find clear empirical evidence of an increase in
the wind-strength over the wind bi-stability region towards lower
temperatures.
Description:
Results from the spectroscopic analysis of the Galactic O9-B5 blue
luminous stars in the sample: Identifiable name in SIMBAD, galactic
longitude, galactic latitude, adopted spectral classification,
projected rotational velocity, macroturbulent broadening, effective
temperature, surface gravity, microturbulence, helium surface
abundance, wind-strength parameter, quality flag, FITS-file in the
format of the IACOB spectroscopic database of the best spectrum, and
S/N ratio. The columns associated to microturbulence, helium surface
abundance, and wind-strength parameter are preceded by an additional
column that indicates which of the four possible scenarios for the
associated probability distribution applies (see Section 3.2.4 of the
manuscript). All parameters except those of the line broadening
include an upper and lower uncertainty.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled1.dat 180 527 Relevant information and analysis results
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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/638/A157 : O-type stars near ZAMS elusive detection (Holgado+, 2022)
J/A+A/665/A150 : Rotational properties of Galactic O-type stars (Holgado+ 2022)
J/A+A/672/A22 : Binarity in fast-rotating O-type stars (Britavskiy+, 2023)
J/A+A/674/A212 : Spectroscopic sample of Galactic O9-B9 SGs (de Burgos+, 2023)
Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Identifiable name of the star
12- 19 F8.4 deg GLON Galactic longitude
21- 28 F8.4 deg GLAT Galactic latitude
30- 42 A13 --- SpC Adopted spectral classification (1)
44 I1 --- n_SpC [1/3]? Note on SpC (1)
46- 48 I3 km/s vsini Projected rotational velocity (2)
50- 52 I3 km/s vmac ? Macroturbulent velocity (3)
54- 58 I5 K Teff Effective temperature
61- 64 I4 K e_Teff Lower uncertainty on effective temperature
66- 69 I4 K E_Teff Upper uncertainty on effective temperature
71- 74 F4.2 [cm/s2] logg Surface gravity (4)
77- 80 F4.2 [cm/s2] e_logg Lower uncertainty on surface gravity
82- 85 F4.2 [cm/s2] E_logg Upper uncertainty on surface gravity
87 A1 --- f_xi Probability distribution flag
(microturbulence)
89- 90 I2 km/s xi Microturbulence
93 I1 km/s e_xi ? Lower uncertainty on microturbulence
95 I1 km/s E_xi ? Upper uncertainty on microturbulence
97 A1 --- f_He [=>d] Probability distribution flag
(helium abundance)
99-102 F4.2 --- He ? Helium surface abundance (N(He)/N(H))
105-108 F4.2 --- e_He ? Lower uncertainty on helium surface
abundance
110-113 F4.2 --- E_He ? Upper uncertainty on helium surface
abundance
115 A1 --- f_logQ [≤>] Probability distribution flag
(wind-strength)
117-121 F5.1 --- logQ ? Wind-strength (Msol/a km/s R/Rsol)
124-126 F3.1 --- e_logQ ? Lower uncertainty on wind-strength
128-130 F3.1 --- E_logQ ? Upper uncertainty on wind-strength
132 I1 --- q [1/4] Quality flag
134-176 A43 --- Ref.file Fits file-name of the used spectrum
178-180 I3 --- S/N Signal-to-noise ratio in 4000-5000A
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Note (1): We adopted the recommended classification quoted in the SIMBAD
astronomical database except for the cases indicated in the n_SpC column as:
1 = de Burgos et al., 2020A&A...643A.116D 2020A&A...643A.116D, Cat. J/A+A/643/A116
2 = de Burgos et al., 2023A&A...674A.212D 2023A&A...674A.212D, Cat. J/A+A/674/A212
3 = Negueruela et al. (submitted).
For HD168021, HD168183, and HD187879, the SIMBAD classification included a
second component, but we have only included the first. We note that in the case
of the O-type stars, most of the classifications are adopted from the GOSSS
series of papers (Sota et al. 2011ApJS..193...24S 2011ApJS..193...24S, Cat. III/274 and
Maiz-Apellaniz et al., 2016ApJS..224....4M 2016ApJS..224....4M, Cat. J/ApJS/224/4).
Note (2): We adopt a global uncertainty for vsini of 15km/s based on the
average value.
Note (3): We adopt a global uncertainty for vmac of 20km/s based on the
average value. Based on the results by Simon-Diaz et al. (2014A&A...570L...6S 2014A&A...570L...6S),
we masked vmac in those cases in which vsini>180km/s.
Note (4): The values of logg have not been corrected for centrifugal forces.
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Acknowledgements:
Abel de Burgos, astroabelink(at)gmail.com
References:
Simon-Diaz & Herrero, 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
Holgado et al., Paper VI 2020A&A...638A.157H 2020A&A...638A.157H, Cat. J/A+A/638/A157
Maiz-Apellaniz & Barba, 2018A&A...613A...9M 2018A&A...613A...9M, Cat. J/A+A/613/A9
Holgado et al., Paper VII 2022A&A...665A.150H 2022A&A...665A.150H, Cat. J/A+A/665/A150
Britavskiy et al., Paper VIII 2023A&A...672A..22B 2023A&A...672A..22B, Cat. J/A+A/672/A22
de Burgos et al., Paper IX 2023A&A...674A.212D 2023A&A...674A.212D, Cat. J/A+A/674/A212
(End) Abel de Burgos [ULL,IAC], Patricia Vannier [CDS] 24-Jun-2024