J/A+A/643/A116 HR study of massive supergiants in Per OB1 (de Burgos+, 2020)
High-resolution spectroscopic study of massive blue and red supergiants in
Per OB1. I. Definition of the sample, membership, and kinematics.
de Burgos A., Simon-Diaz S., Lennon D.J., Dorda R., Negueruela I.,
Urbaneja M.A., Patrick L.R., Herrero A.
<Astron. Astrophys. 643, A116 (2020)>
=2020A&A...643A.116D 2020A&A...643A.116D (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Spectroscopy ; Stars, supergiant
Keywords: open clusters and associations: individual: Per OB1 -
stars: early type - stars: late-type -
binaries: spectroscopic - stars: evolution - astrometry
Abstract:
The Perseus OB1 association, including the h and chi Persei double
cluster, is an interesting laboratory for the investigation of massive
star evolution as it hosts one of the most populous groupings of blue
and red supergiants (Sgs) in the Galaxy at a moderate distance and
extinction. We discuss whether the massive O-type, and blue and red Sg
stars located in the Per OB1 region are members of the same
population, and examine their binary and runaway status. We gathered a
total of 405 high-resolution spectra for 88 suitable candidates around
4.5 deg from the center of the association, and compiled astrometric
information from Gaia DR2 for all of them. This was used to
investigate membership and identify runaway stars. By obtaining
high-precision radial velocity (RV) estimates for all available
spectra, we investigated the RV distribution of the global sample (as
well as different subsamples) and identified spectroscopic binaries
(SBs). Most of the investigated stars belong to a physically linked
population located at d=2.5±0.4kpc. We identify 79 confirmed or
likely members, and 5 member candidates. No important differences are
detected in the distribution of parallaxes when stars in h and chi
Persei or the full sample are considered. In contrast, most O-type
stars seem to be part of a differentiated population in terms of
kinematical properties. In particular, the percentage of runaways
among them (45%) is considerable higher than for the more evolved
targets (which is lower than ∼5% in all cases). A similar tendency is
also found for the percentage of clearly detected SBs, which already
decreases from 15% to 10% when the O star and B Sg samples are
compared, respectively, and practically vanishes in the cooler Sgs.
Concerning this latter result, our study illustrates the importance of
taking the effect of the ubiquitous presence of intrinsic variability
in the blue-to-red Sg domain into account to avoid the spurious
identification of pulsating stars as SBs. All but 4 stars in our
working sample (including 10 O giants/Sgs, 36 B Sgs, 9 B giants, 11
A/F Sgs, and 18 red Sgs) can be considered as part of the same
(interrelated) population. However, any further attempt to describe
the empirical properties of this sample of massive stars in an
evolutionary context must take into account that an important fraction
of the O stars is or likely has been part of a binary/multiple system.
In addition, some of the other more evolved targets may have also been
affected by binary evolution. In this line of argument, it is also
interesting to note that the percentage of spectroscopic binaries
within the evolved population of massive stars in Per OB1 is lower by
a factor 4-5 than in the case of dedicated surveys of O-type stars in
other environments that include a much younger population of massive
stars.
Description:
List of stars in the sample and some missing supergiants from Per OB1.
Spectral classification, Gaia DR2 coordinates, photometry and
astrometry, and radial velocity for the best spectrum. For stars with
5 or more spectra (excluding binaries) and for SB1 with multi-epoch
data: time-span, number of spectra, average radial velocity and
peak-to-peak variation. For all the stars in the sample, membership
classification including whether or not each star has parallax, total
proper motion, and radial velocities within 2-sigma from the mean of
each distribution. Spectral variability is also indicated together
with comments.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 118 108 Sample of stars within 4.5 degrees of Per OB1
tablea2.dat 52 15 Radial velocities for stars with ≥5 spectra
(no SB1/SB2)
tablea3.dat 52 4 Radial velocities for confirmed SB1 stars
with multi-epoch
tablea4.dat 69 88 Membership and features of investigated stars
tablea5.dat 46 402 Radial velocity measurements for individual epochs
for the 88 stars of table 4
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Name of the star
10 A1 --- n_Name [*] Note (3)
12- 23 A12 --- SpType Spectral classification
25- 26 I2 h RAh Right ascension (J2000) (1)
28- 29 I2 min RAm Right ascension (J2000) (1)
31- 36 F6.3 s RAs Right ascension (J2000) (1)
38 A1 --- DE- Declination sign (J2000) (1)
39- 40 I2 deg DEd Declination (J2000) (1)
42- 43 I2 arcmin DEm Declination (J2000) (1)
45- 49 F5.2 arcsec DEs Declination (J2000) (1)
51- 53 F3.1 mag Gmag G magnitude from Gaia DR2
55- 57 F3.1 mag BP-RP BP-RP colour from Gaia DR2
59- 65 F7.3 mas/yr pmRA* Proper motion along RA (pmRA*cosDE)
67- 71 F5.3 mas/yr e_pmRA* rms uncertainty on pmRA*
72 A1 --- n_pmRA* [)] ) if RUWE value is higher than 1.4
74- 79 F6.3 mas/yr pmDE Proper motion along DE
81- 85 F5.3 mas/yr e_pmDE rms uncertainty on pmDE
86 A1 --- n_pmDE [)] ) if RUWE value is higher than 1.4
88- 93 F6.3 mas plx Parallax (2)
95- 99 F5.3 mas e_plx rms uncertainty on plx (2)
100 A1 --- n_plx [)] ) if RUWE value is higher than 1.4
102-107 F6.1 km/s RV ? Radial velocity of best S/N spectrum
109-111 F3.1 km/s e_RV ? Uncertainty on RVel
113-118 A6 --- Notes Notes for the target
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Note (1): Sky coordinates retrieved from Gaia DR2.
Note (2): Parallaxes retrieved from Gaia DR2 are corrected from a -0.03 mas
zero-point offset.
Note (3): Notes as follows:
HD14528 = proper motion and parallax taken from
Asaki et al. (2010ApJ...721..267A 2010ApJ...721..267A)
HD13970, HD13402, HD15558 = Stars identified as SB2. The radial velocity
measurements refer to the main component (top line) and
second component (bottom line).
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Byte-by-byte Description of file:tablea[23].dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Name of the star
10- 20 A11 --- SpType Spectral classification
22- 25 I4 d TimeSpan Time-span of the spectra
27- 28 I2 --- Nspectra Number of spectra
30- 34 F5.1 km/s RVmean Average radial velocity
36- 39 F4.1 km/s e_RVmean Uncertainty of RVmean
41- 46 F6.2 km/s RVpp Peak-to-peak radial velocity
48- 52 F5.2 km/s e_RVpp Uncertainty of RVpp
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Name of the star
11 A1 --- fPlx [ocx] Flag for parallax (1)
12 A1 --- n_fPlx [)] Bad astrometry (see column Comments)
14 A1 --- fPM [ocx] Flag for total proper motion (1)
15 A1 --- n_fPM [)] Bad astrometry (see column Comments)
17 A1 --- fRVbest [ocx] Flag for RV of the best spectrum (1)
19 A1 --- fRVmulti [ocx-] Flag for RV from multiepoch data (1)
21 A1 --- fRVfinal [ocx] Flag for final RV (1)
22 A1 --- n_fRVfinal [)] Binaries or potential binaries (2)
24- 32 A9 --- SpecVar Cause of spectral variability
34 A1 --- Member [YLCN] Membership to Per OB1 (3)
36- 69 A34 --- Comments Comments (4)
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Note (1): Flags as follows:
o = stars within 2-sigma from the mean of the distribution
c = outliers by more than 2-sigma from the mean of the distribution
x = outliers by more than 3-sigma from the mean of the distribution
For RVbest, the 2-sigma was computed separately for O, B, A/F, and
K/M spectral types.
For RVmulti, the 2-sigma was computed independently for each spectral type,
taking stars with more than one spectrum into account, but only applying
the boundaries stars with more than three spectra.
Note (2): For the column n_fRVfinal, parentheses correspond to stars that are
binaries or potential binaries with fewer than four spectra and a time span
shorter than 500 days.
Note (3): Flags as follows:
Y = members of Per OB1
L = likely member of Per OB1
C = candidate to be a member of Per OB1
N = nonmember of Per OB1
HD13268 has higher parallax than the average, it is considered a member
because of its high negative RV.
Note (4): Notes and references as follows:
Runaway = runaway stars according to proper motion alone (PM),
and also according to RV (PM+RV)
Runaway? = same as previous, but they are already identified as binaries
SB1? = stars with four or fewer spectra and a time span shorter
than 500 days that are outliers only in RV
RUWE = stars with poor astrometry because the Gaia RUWE is higher
than 1.4
Runaway(PM/RV) = runaway stars according to proper motion (PM) or/and radial
velocity (RV)
EA = betaPersei-type (Algol) eclipsing systems
EB = eclipsing binaries
ELL = close binary systems with ellipsoidal components
Hel73 = Abt & Levy, 1973ApJ...184..167A 1973ApJ...184..167A
Zac85 = Zakirov & Shaidullin, 1985AbaOB..58..313Z 1985AbaOB..58..313Z
Lau17 = Laur et al., 2017A&A...598A.108L 2017A&A...598A.108L
Hol18 = Holgado et al., 2018A&A...613A..65H 2018A&A...613A..65H, Cat. J/A+A/613/A65
MA19 = Maiz Apellaniz et al., 2019A&A...626A..20M 2019A&A...626A..20M, Cat. J/A+A/626/A20
Hol20 = Holgado et al., 2020arXiv200505446H 2020arXiv200505446H
VSI = The International Variable Star Index, Cat. B/vsx
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Byte-by-byte Description of file: tablea5.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Name of the star
10 A1 --- n_Name [*] Note (1)
12- 23 A12 --- SpType Spectral classification
25- 26 I2 --- Nlines Number of lines used for determine the RV
28- 34 F7.1 d MBJD Modified Barycentric Julian Date
36- 41 F6.1 km/s RV Radial velocity measurement
43- 46 F4.1 km/s e_RV Uncertainty of RV
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Note (1): Stars identified as SB2. The values in this table only refer to the
main component.
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Acknowledgements:
Abel de Burgos, astroabelink(at)gmail.com
(End) A. de Burgos [ULL], S. Simon-Diaz [IAC], P. Vannier [CDS] 16-Oct-2020