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Binarity at LOw Metallicity (BLOeM) Projected rotational velocities★

Lennon, D. J. ; Berlanas, S. R. ; Herrero, A. ; Britavskiy, N. ; Dufton, P. L. ; Langer, N. ; Jin, H. ; Schootemeijer, A. ; Menon, A. and Bestenlehner, J. , et al. (2026) In Astronomy and Astrophysics 707.
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). We present projected rotational velocities (v sin i) of all sources, and, using the multiplicity properties presented in previous papers, we derive the v sin i 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... (More)

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). We present projected rotational velocities (v sin i) of all sources, and, using the multiplicity properties presented in previous papers, we derive the v sin i 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 v sin i values, but with a strong peak in the distribution in the range 30–60 km s−1, which is close to the resolution limit of ∼30 km s−1, indicating the presence of many upper limits. Sources in this low v sin i 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 v sin i cohort, which 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 their v sin i estimates are distributed around a mean value of ∼140 km s−1. Higher v sin i sources are also present in the single and SB1 systems, all of which have a tail to higher v sin i values. This is consistent with tidal and mass-transfer effects. The supergiants, with a few exceptions, have low v sin i, and the bulk of these systems is essentially unresolved at the current spectral resolution (∼30 km s−1).

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type
Contribution to journal
publication status
published
subject
keywords
binaries: spectroscopic, Magellanic Clouds, stars: early-type, stars: evolution, stars: massive, stars: rotation
in
Astronomy and Astrophysics
volume
707
article number
A204
publisher
EDP Sciences
external identifiers
  • scopus:105032364123
ISSN
0004-6361
DOI
10.1051/0004-6361/202558539
language
English
LU publication?
yes
additional info
Publisher Copyright: © The Authors 2026.
id
c5c3a8a4-e997-4b31-ac92-f0a1b7433025
date added to LUP
2026-04-23 14:12:04
date last changed
2026-04-27 15:34:23
@article{c5c3a8a4-e997-4b31-ac92-f0a1b7433025,
  abstract     = {{<p>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). We present projected rotational velocities (v sin i) of all sources, and, using the multiplicity properties presented in previous papers, we derive the v sin i 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 v sin i values, but with a strong peak in the distribution in the range 30–60 km s<sup>−1</sup>, which is close to the resolution limit of ∼30 km s<sup>−1</sup>, indicating the presence of many upper limits. Sources in this low v sin i 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 v sin i cohort, which 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 their v sin i estimates are distributed around a mean value of ∼140 km s<sup>−1</sup>. Higher v sin i sources are also present in the single and SB1 systems, all of which have a tail to higher v sin i values. This is consistent with tidal and mass-transfer effects. The supergiants, with a few exceptions, have low v sin i, and the bulk of these systems is essentially unresolved at the current spectral resolution (∼30 km s<sup>−1</sup>).</p>}},
  author       = {{Lennon, D. J. and Berlanas, S. R. and Herrero, A. and Britavskiy, N. and Dufton, P. L. and Langer, N. and Jin, H. and Schootemeijer, A. and Menon, A. and Bestenlehner, J. and Crowther, P. and Vink, J. S. and Bodensteiner, J. and Shenar, T. and Deshmukh, K. and Villaseñor, J. I. and Patrick, L. and Najarro, F. and De Koter, A. and Mahy, L. and Bowman, D. M. and Bobrick, A. and Evans, C.J. and Gull, M. and Holgado, G. and Katabi, Z. and Kubát, J. and Marchant, P. and Pauli, D. and Pawlak, M. and Renzo, M. and Rocha, D. F. and Sander, A. A.C. and Sayada, T. and Simón-Díaz, S. and Stoop, M. and Valli, R. and Wang, C. and Xu, X. T.}},
  issn         = {{0004-6361}},
  keywords     = {{binaries: spectroscopic; Magellanic Clouds; stars: early-type; stars: evolution; stars: massive; stars: rotation}},
  language     = {{eng}},
  month        = {{03}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{Binarity at LOw Metallicity (BLOeM) Projected rotational velocities★}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/202558539}},
  doi          = {{10.1051/0004-6361/202558539}},
  volume       = {{707}},
  year         = {{2026}},
}