J/A+A/698/A40 BLOeM. SMC early B supergiants multiplicity (Britavskiy+, 2025)
Binarity at LOw Metallicity (BLOeM):
Multiplicity of early B-type supergiants in the SMC.
Britavskiy N., Mahy L., Lennon D.J., Patrick L.R., Sana H., Villasenor J.I.,
Shenar T., Bodensteiner J., Bernini-Peron M., Berlanas S.R., Bowman D.M.,
Crowther P.A., de Mink S.E., Evans C.J., Goetberg Y., Holgado G.,
Johnston C., Keszthelyi Z., Klencki J., Langer N., Mandel I., Menon A.,
Moe M., Oskinova L.M., Pauli D., Pawlak M., Ramachandran V., Renzo M.,
Sander A.C., Schneider F.R.N., Schootemeijer A., Sen K., Simon-Diaz S.,
van Loon J.T., Vink J.S.
<Astron. Astrophys. 698, A40 (2025)>
=2025A&A...698A..40B 2025A&A...698A..40B (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Populations, stellar ; Stars, supergiant ;
Stars, B-type ; Binaries, spectroscopic
Keywords: binaries: general - binaries: spectroscopic - stars: early-type -
stars: massive - supergiants
Abstract:
The blue supergiant (BSG) domain contains a large variety of stars for
which the past and future evolutionary paths are still highly
uncertain. As binary interaction plays a crucial role in the fate of
massive stars, investigating the multiplicity among BSGs sheds light
on the fate of such objects.
We aim to estimate the binary fraction of a large sample of BSGs in
the Small Magellanic Cloud within the BLOeM survey.
In total, we selected 262 targets with spectral types B0-B3, and
luminosity classes I-II. This work is based on spectroscopic data
collected by the GIRAFFE instrument mounted on the Very Large
Telescope, which gathered nine epochs within three months.
Our spectroscopic analysis for each target includes individual and
peak-to-peak radial velocity measurements, investigation of the line
profile variability, and a periodogram analysis for searching for
possible short- and long-period binaries. By applying a 20km/s
threshold on the peak-to-peak radial velocities above which we
consider the star to be binary, the resulting observed spectroscopic
binary fraction for our BSG sample is 23±3%. Independent analysis of
line profile variability reveals 11 (plus 5 candidates) double-lined
spectroscopic binaries and 32 (plus 41 candidates) single-lined
spectroscopic binaries. Based on these results, we estimate the
overall observed binary fraction in this sample to be 34±3%, which
is similar to the computed intrinsic binary fraction of 40±4%. In
addition, we derived reliable orbital periods for 41 spectroscopic
binaries and potential binary candidates among which there are 17
eclipsing binaries, including 20 SB1 and SB2 systems with periods less
than 10 days. We report a significant drop in the binary fraction of
BSGs with spectral types later than B2 and effective temperatures less
than 18kK, which could indicate the end of main sequence phase at this
temperature regime.
We found no metallicity dependence in the binary fraction of BSGs
compared to existing spectroscopic surveys of the Galaxy and Large
Magellanic Cloud.
Description:
We present basic information and our spectroscopic binary
classification for 262 early B-type supergiants (B0-B3 spectral types
and luminosity classes I-II) in the Small Magellanic Cloud within the
BLOeM campaign based on 9 epochs of spectroscopic observations.
Table B1: BLOeM ID, GAIA DR3 ID, spectral type, number of available
epochs, peak-to-peak radial velocity variation, effective temperature,
luminosity, estimated radii, possible periods of RV variations,
evolutionary masses, spectroscopic binary status, and notes.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 145 262 Basic information about working sample of BSGs
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See also:
J/A+A/690/A289 : Binarity at LOw Metallicity (BLOeM). I. (Shenar+, 2024)
J/A+A/698/A38 : BLOeM. Oe and Be stars (Bodensteiner+, 2025)
J/A+A/698/A39 : BLOeM. BAF-type supergiants (Patrick+, 2025)
J/A+A/698/A41 : BLOeM. Early B dwarfs and giants at Z=0.2 (Villasenor+, 2025)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- BLOeM BLOeM identifier (N-NNN)
7- 25 I19 --- GaiaDR3 Gaia Data Release 3 identifier
27- 36 A10 --- SpType Spectral type (1)
37- 38 I2 --- Nepochs Number of available epochs
40- 45 F6.2 km/s RVpp Peak-to-peak radial velocity measurements
47- 50 F4.1 km/s e_RVpp Peak-to-peak radial velocity measurements error
52- 56 I5 K Teff Estimated effective temperatures (1)
58- 61 F4.2 [Lsun] logL Estimated luminosities (1)
63- 66 F4.1 Rsun R Estimated radii
68- 73 F6.2 d Porb ? Estimated periods of RV variations
74 A1 --- n_Porb [*] note on Porb (2)
76- 79 F4.1 Msun Mass Estimated evolutionary masses
(Bestenlehner et al. in prep.)
81- 87 A7 --- Bin Spectroscopic binary status for each of the
stars (3)
89-145 A57 --- Notes Additional notes (4)
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Note (1): from Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289)
Note (2): Those periods that are marked with "*" are taken from the OGLE-IV
database Pawlak et al. (2016AcA....66..421P 2016AcA....66..421P, Cat. J/AcA/66/421)
i.e. these targets are eclipsing binaries.
Note (3): Binary status as follows:
-- = apparently single
SB1 = one component spectroscopic binary
SB2 = double-lined spectroscopic binary
lpv/SB1 = line profile variable or one component non-prominent
spectroscopic binary
SB1/SB2? = spectroscopic binary
Note (4): The "Notes" column explanation:
(ULLYSES) = this BSG has been studied within the ULLYSES
survey (Bernini-Peron et al.,
2024A&A...692A..89B 2024A&A...692A..89B)
broad line profiles = possible fast equatorial rotation
low S/N = low signal-to-noise ratio of the spectra i.e.
below 50
possible long period binary = it means there are prominent peaks in the
long-period ranges (>200 days) on the
Lomb-Scargle periodogram
another period = it means there are prominent peaks in the
long-period ranges (>200 days) on the
Lomb-Scargle periodogram
EB = eclipsing binary
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Acknowledgements:
Nikolay Britavskiy, britvavskiy(at)gmail.com
References:
Shenar et al., Paper I 2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289
(End) Patricia Vannier [CDS] 04-Mar-2025