J/MNRAS/513/5847 Red supergiant stars in binary systems. I. SMC (Patrick+, 2022)
Red supergiant stars in binary systems.
I. Identification and characterisation in the Small Magellanic Cloud from the
UVIT ultraviolet imaging survey.
Patrick L.R., Thilker D., Lennon D.J., Bianchi L., Schootemeijer A.,
Dorda R., Langer N., Negueruela I.
<Mon. Not. R. Astron. Soc. 513, 5847 (2022)>
=2022MNRAS.513.5847P 2022MNRAS.513.5847P (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, supergiant ;
Stars, double and multiple ; Ultraviolet
Keywords: binaries: general - stars: late-type - stars: massive -
Magellanic Clouds - ultraviolet: stars
Abstract:
We aim to identify and characterise binary systems containing red
supergiant (RSG) stars in the Small Magellanic Cloud (SMC) using a
newly available ultraviolet (UV) point source catalogue obtained using
the Ultraviolet Imaging Telescope (UVIT) on board AstroSat. We select
a sample of 561 SMC RSGs based on photometric and spectroscopic
observations at optical wavelengths and cross-match this with the
far-UV point source catalogue using the UVIT F172M filter, finding 88
matches down to an AB magnitude of 20.3, which we interpret as hot
companions to the RSGs. Stellar parameters (luminosities, effective
temperatures and masses) for both components in all 88 binary systems
are determined and we find mass distributions in the ranges
6.2<M/M☉<20.3 for RSGs and 3.7<M/M☉<15.6 for their
companions. The most massive RSG binary system in the SMC has a
combined mass of 30±2M☉, with a mass ratio (q) of 0.94. To
determine the intrinsic multiplicity fraction for RSGs in the SMC, we
simulate observational biases and find 18.8±1.5% for mass ratios in
the range 0.3<q<1.0 and orbital periods approximately in the range
3<logP[days]<8. By comparing our results with those of a similar mass
on the main-sequence, we determine the fraction of single stars to be
∼20% and argue that the orbital period distribution declines rapidly
beyond logP∼3.5. We study the mass-ratio distribution of RSG binary
systems and find that a uniform distribution best describes the data
below 14M☉. Above 14M☉, we find a lack of high mass-ratio
systems.
Description:
The initial source catalogue of RSGs is based on that of Yang et al.
(2020A&A...639A.116Y 2020A&A...639A.116Y, Cat. J/A+A/639/A116, hereafter YB20). These
authors constructed an RSG catalogue in the SMC principally based on
five different photometric criteria from colour-magnitude diagrams
(CMDs) at different wavelengths from the SMC point source catalogue
of Yang et al. (2019A&A...629A..91Y 2019A&A...629A..91Y, Cat. J/A+A/629/A91). These
criteria are anchored on the appearance of the RSG population within
the MESA Isochrones and Stellar Tracks (MIST; Choi et al.,
2016ApJ...823..102C 2016ApJ...823..102C; Dotter, 2016ApJS..222....8D 2016ApJS..222....8D). YB20 developed a
ranking system ranging from -1 to 5, depending on the criteria met by
each source to qualify as an RSG candidate. Ranks 4-5 flag sources
with a low probability to be an RSG. As an initial source catalogue,
we select 1233 targets from YB20 with ranks between -1 and 3, which
correspond to either targets that have a spectroscopic classification
as an RSG (rank -1) or with at least two independent photometric
classifications (ranks 0 to 3).
With this initial source catalogue, we cross-match all targets with
the Gaia EDR3 data release (Gaia Collaboration, 2021A&A...649A...1G 2021A&A...649A...1G,
Cat. I/350) using MAST Casjobs interface.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 142 862 RSG full sample
tablea2.dat 212 88 RSG binary systems
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/A+A/629/A91 : A source catalog for the SMC (Yang+, 2019)
J/A+A/639/A116 : RSGs in the SMC (Yang+, 2020)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 30 A30 --- Name Name
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 45 F8.5 s RAs Right ascension (J2000)
47 A1 --- DE- Declination sign (J2000)
48- 49 I2 deg DEd Declination (J2000)
51- 52 I2 arcmin DEm Declination (J2000)
54- 60 F7.4 arcsec DEs Declination (J2000)
62- 66 F5.2 mag J2mag ? 2MASS J-band magnitude
68- 71 F4.2 mag e_J2mag ? Error on 2MASS J-band magnitude
73- 77 F5.2 mag Ks2mag ? 2MASS Ks-band magnitude
79- 82 F4.2 mag e_Ks2mag ? Error on 2MASS Ks-band magnitude
84- 88 F5.3 mag E(V-I) Reddening from Skowron+2021
90- 94 F5.3 mag e_E(V-I) Negative error on E(V-I)
96-100 F5.3 mag E_E(V-I) Positive error on E(V-I)
102-105 F4.2 mag AV V-band extinction
107-111 F5.3 mag e_AV Negative error on AV
113-117 F5.3 mag E_AV Positive error on AV
119-122 F4.1 Msun Mrsg RSG mass
124-126 F3.1 Msun e_Mrsg Error on RSG mass
128-131 I4 K Teffrsg ? RSG effective temperature
133-136 F4.2 [Lsun] logLrsg ? RSG luminosity
138-142 F5.3 [Lsun] e_logLrsg ? Error on RSG luminosity
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 30 A30 --- Name Name
32- 47 F16.13 deg RAdeg Right ascension (J2000)
49- 65 F17.13 deg DEdeg Declination (J2000)
67- 71 F5.2 mag F172Mmag F172M UVIT magnitude (AB)
73- 76 F4.2 mag e_F172Mmag Error on F172M UVIT magnitude (AB)
78- 82 F5.2 mag J2mag 2MASS J-band magnitude
84- 87 F4.2 mag e_J2mag Error on 2MASS J-band magnitude
89- 93 F5.2 mag Ks2mag 2MASS Ks-band magnitude
95- 98 F4.2 mag e_Ks2mag Error on Ks-band magnitude
100-104 F5.3 mag E(V-I) Reddening from Skowron+2021
106-110 F5.3 mag e_E(V-I) Negative error on E(V-I)
112-116 F5.3 mag E_E(V-I) Positive error on E(V-I)
118-121 F4.2 mag AV V-band extinction
123-127 F5.3 mag e_AV Negative error on AV
129-133 F5.3 mag E_AV Positive error on AV
135-138 F4.1 Msun Mrsg RSG mass
140-144 F5.3 Msun e_Mrsg Error on RSG mass
146-149 I4 K Teffrsg RSG effective temperature
151-154 F4.2 [Lsun] logLrsg RSG luminosity
156-160 F5.3 [Lsun] e_logLrsg Error on RSG luminosity
162-165 F4.1 Msun M2 Companion mass
167-169 F3.1 Msun e_M2 Error on companion mass
171-174 F4.2 K Teff2 Companion effective temperature
176-180 F5.3 K E_Teff2 Positive error on Teff2
182-186 F5.3 K e_Teff2 Negative error on Teff2
188-192 F5.3 [Lsun] logL2 Companion luminosity
194-198 F5.3 [Lsun] E_logL2 Positive error on logL2
200-204 F5.3 [Lsun] e_logL2 Negative error on logL2
206-210 F5.2 --- dRV ?=- RV difference from Dorda & Patrick
(2021MNRAS.502.4890D 2021MNRAS.502.4890D)
212 I1 --- FlagN20 [0/1] Flagged as RSG binary in Neugent et al.
(2020ApJ...889...44N 2020ApJ...889...44N)
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Acknowledgements:
Lee Patrick, lee(at)lrp-astro.org
(End) Patricia Vannier [CDS] 04-Mar-2022