J/A+A/707/A204 BLOeM. Projected rotational velocities (Lennon+, 2026)
Binarity at LOw Metallicity (BLOeM): Projected rotational velocities.
Lennon D.J., Berlanas S.R., Herrero A.D., Britavskiy N., Dufton P.L.,
Langer N., Jin H., Schootemeijer A., Menon A., Bestenlehner J.M.,
Crowther P.A., Vink J., Bodensteiner J., Shenar T., Deshmukh K.,
Villasenor J.I., Patrick L., Najarro F., de Koter, A., Mahy L.,
Bowmnan D.M., Bobrick A., Evans C.J., Gull M., Holgado G., Katabi Z.,
Kubat J., Marchant P., Pauli D., Pawlak M., Renzo M., Rocha D.F.,
Sander A.A.C., Sayada T., Simon-Diaz S., Stoop M., Valli R., Wang C.,
Xu X.-T.
<Astron. Astrophys. 707, A204 (2026)>
=2026A&A...707A.204L 2026A&A...707A.204L (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, OB ; Rotational velocities ;
Optical
Keywords: binaries: spectroscopic - stars: early-type - stars: evolution -
stars: massive - stars: rotation - Magellanic Clouds
Abstract:
The Binarity at LOw Metallicity (BLOeM) survey is an ESO large
programme designed to obtain multi-epoch spectroscopy for 929 massive
stars in the Small Magellanic Cloud (SMC). It will provide binary
fractions and orbital configurations of binary systems, and search for
dormant black-hole binary candidates (OB+BH). Here we present
projected rotational velocities (vsini) of all sources and, using the
multiplicity properties presented in previous papers, we derive the
vsini distributions of apparent single stars, single lined
spectroscopic (SB1) binaries, and SB2 systems. We identify a locus in
the Hertzsprung-Russell diagram where rotational velocities decrease
significantly; we interpret this feature as broadly corresponding to
the terminal-age main sequence. The main sequence cohort is
distinguished by a broad range of vsini values, but with a strong peak
in the distribution in the range 30-60km/s, close to the resolution
limit of ∼30km/s. Sources in this low vsini peak are distributed
throughout the main sequence, and are also present in the SB1 sample,
though less prominent than in the single star distribution. A
preliminary analysis of the lowest vsini cohort, that includes SB1
systems, implies that roughly one third may be nitrogen rich and we
speculate that this cohort is a mix of pristine single stars, long
period binaries, and merger products. The SB2 systems appear to be
mostly short period binaries in synchronous rotation and have vsini
estimates distributed around a mean value of ∼140km/s. Higher vsini
sources are also present in the single and SB1 systems, all of which
have tail to higher vsini values, consistent with tidal and
mass-transfer effects. The supergiants, with a few exceptions, have
low vsini, the bulk of these systems being essentially unresolved at
current spectral resolution (∼30km/s).
Description:
We present projected rotational velocities for 929 sources from the
multi-epoch Binarity at LOw Metallicity (BLOeM) spectroscopic survey
of the Small Magellanic Cloud using VLT/Flames.
Table 1: Projected rotational velocities of all BLOeM stars from
Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289) obtained
using the Fourier transform (FT) and full-width half-maximum (FWHM)
methods. Projected rotational velocities for the 70 SB2 systems listed
in Table 2 should be preferred to the values in this table.
Table 2: Projected rotational velocities for both components,
labeled A and B, of 70 SB2 systems obtained using the HeI 4387Å
line. These were determined using the FWHM approach (Gaussian
fitting). To facilitate identification of A and B, the central
wavelengths of each HeI 4387 A component, waveA and waveB, are
also listed for a specific observation with epoch number nepoch.
Table C.1: Master table listing additional auxiliary information
for convenience. Stellar parameters and binary status are from
Bestenlehner et al (2025MNRAS.540.3523B 2025MNRAS.540.3523B, Cat. J/MNRAS/540/3523),
Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289),
Sana et al. (2025NatAs...9.1337S 2025NatAs...9.1337S, Cat.J/other/NatAs/9.1337),
Bodensteiner et al. (2025A&A...698A..38B 2025A&A...698A..38B, Cat. J/A+A/698/A38),
Villasenor et al. (2025A&A...698A..41V 2025A&A...698A..41V, Cat. J/A+A/698/A41),
Britavskiy et al. (2025A&A...698A..40B 2025A&A...698A..40B, Cat. J/A+A/698/A40)
and Patrick et al. (2025A&A...698A..39P 2025A&A...698A..39P, Cat. J/A+A/698/A39).
In additional a number of data flags denoted demographic groups
as follows:
field: Field number for that source
pflag: source of stellar parameters
= -1 no parameters available
= 0 parameters from Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S)
= 1 parameters from Bestenlehner at al. (2025MNRAS.540.3523B 2025MNRAS.540.3523B)
= 2 parameters from Patrick et al. (2025A&A...698A..39P 2025A&A...698A..39P)
mflag: multiplicity flag
= -1 not set
= 0 assumed single
= 1 not used
= 2 SB1
= 3 SB2
gflag: group flag
= 0 O-stars
= 1 B-type dwarfs and giants
= 2 B-type supergiants and bright giants
= 3 OBe star
= 4 BAF supergiants
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 31 929 Projected rotational velocities of BLOeM stars
table2.dat 43 72 Projected rotational velocities of selected
SB2 primary and secondary components
tablec1.dat 81 929 Master table listing preferred vsini values
and auxiliary information
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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/A40 : BLOeM. SMC early B supergiants multiplicity
(Britavskiy+, 2025)
J/A+A/698/A41 : BLOeM. Early B dwarfs and giants at Z=0.2
(Villasenor+, 2025)
J/MNRAS/540/3523 : BLOeM. Physical properties of OB stars
(Bestenlehner+, 2025)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- BLOeM BLOeM identifier (N-NNN) (1)
7- 9 I3 km/s vsiniFT Projected rotational velocity using FT
11- 13 I3 km/s E_vsiniFT Error on FT vsini (upper)
16- 17 I2 km/s e_vsiniFT Error on FT vsini (lower)
19- 20 I2 --- nFT Number of FT measurements
22- 24 I3 km/s vsiniFWHM Projected rotational velocity using FWHM
26- 28 I3 km/s e_vsiniFWHM Error on FWHM vsini
30- 31 I2 --- nFWHM Number of FWHM measurements
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Note (1): From Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- BLOeM BLOeM identifier (N-NNN) (1)
7- 9 I3 km/s vsiniA Projected rotational velocity of A component
12- 13 I2 km/s e_vsiniA Error on vsiniA
15- 17 I3 km/s vsiniB Projected rotational velocity of B component
20- 21 I2 km/s e_vsiniB Error on vsiniB
23- 24 I2 --- Nvsini Number of measurements
26- 32 F7.2 0.1nm waveA Wavelength of component A
34- 40 F7.2 0.1nm waveB Wavelength of component B
42- 43 I2 --- NEpoch Epoch number for WaveA and WaveB
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Note (1): From Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289).
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- BLOeM BLOeM identifier (N-NNN) (1)
7- 21 A15 --- Sptype Spectral type (1)
24- 30 A7 --- Bstatus Binary status (2)
32- 34 I3 km/s vsini Selected projected rotational velocity
36- 38 I3 km/s E_vsini Error on vsini (upper)
40- 42 I3 km/s e_vsini Error on vsini (lower)
44- 48 I5 K Teff Adopted effective temperature
50- 53 F4.2 [Lsun] logL Logarithm of luminosity
56- 59 F4.1 Msun Mevol Evolutionary mass
61- 65 F5.1 Rsun Rstar Stellar radius
67- 69 I3 km/s vcrit Critical velocity
72 I1 --- Field Field number
74- 75 I2 --- pflag Stellar parameters source flag
77- 78 I2 --- mflag Multiplicity flag
81 I1 --- gflag Group flag
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Note (1): Shenar et al. (2024A&A...690A.289S 2024A&A...690A.289S, Cat. J/A+A/690/A289).
Note (2): References for binary status are:
Bodensteiner et al. (2025A&A...698A..38B 2025A&A...698A..38B, Cat. J/A+A/698/A38)
Villasenor et al. (2025A&A...698A..41V 2025A&A...698A..41V, Cat. J/A+A/698/A41)
Britavskiy et al. (2025A&A...698A..40B 2025A&A...698A..40B, cat. J/A+A/698/A40)
Patrick et al. (2025A&A...698A..39P 2025A&A...698A..39P, cat. J/A+A/698/A39)
Sana et al. (2025NatAs...9.1337S 2025NatAs...9.1337S, Cat.J/other/NatAs/9.1337)
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Acknowledgements:
Daniel Lennon, dlennon(at)iac.es
(End) Daniel Lennon [IAC], Patricia Vannier [CDS] 28-Jan-2026