J/other/NatAs/9.1337 RVs of O-type stars in BLOeM survey (Sana+, 2025)
A high fraction of close massive binary stars at low metallicity.
Sana H., Shenar T., Bodensteiner J., Britavskiy N., Langer N., Lennon D.J.,
Mahy L., Mandel I., de Mink S.E., Patrick L.R., Villasenor J.I.,
Abdul-Masih M., Almeida L.A., Backs F., Berlanas S.R., Bernini-Peron M.,
Bowman D.M., Bronner V.A., Crowther P.A., Deshmukh K., Evans C.J., Fabry M.,
Gieles M., Gilkis A., Gonzalez-Tora G., Grafener G., Gotberg Y.,
Hawcroft C., Henault-Brunet V., Herrero A., Holgado G., de Koter A.,
Janssens S., Johnston C., Josiek J., Justham S., Kalari V.M., Klencki J.,
Kubat J., Kubatova B., Lefever R.R., van Loon J.T., Ludwig B., Mackey J.,
Maiz Apellaniz J., Maravelias G., Marchant P., Mazeh T., Menon A., Moe M.,
Najarro F., Oskinova L.M., Ovadia R., Pauli D., Pawlak M., Ramachandran V.,
Renzo M., Rocha D.F., Sander A.A.C., Schneider F.R.N., Schootemeijer A.,
Schosser E.C., Schurmann C., Sen K., Shahaf S., Simon-Diaz S.,
van Son L.A.C., Stoop M., Toonen S., Tramper F., Valli R., Vigna-Gomez A.,
Vink J.S., Wang C., Willcox R.
<Nature Astronomy, 9, 1337-1346 (2025)>
=2025NatAs...9.1337S 2025NatAs...9.1337S (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Binaries, spectroscopic ; Stars, O ;
Radial velocities
Keywords: binaries: spectroscopic - stars: early-type - stars: evolution -
Magellanic Clouds
Abstract:
The interpretation of observations of gravitational waves, transients,
and distant galaxies in the high-redshift Universe heavily relies on
our understanding of massive stars at low metallicity. At high
metallicity, a majority of massive stars have at least one close
stellar companion, which dramatically impacts their evolution,
feedback, and final fate. At low metallicity, constraints on the
multiplicity of massive stars over the separation range leading to
binary interaction have been crucially missing. Here we show that the
presence of massive stars in close binaries is ubiquitous, even at low
metallicity. The Small Magellanic Cloud is a neighbouring
low-metallicity dwarf galaxy with a metal content of about one fifth
solar, hence similar to metallicity environments during and before the
peak of star formation in the Universe. Using Very Large Telescope
spectroscopy from the Binarity at LOw Metallicity large program, we
obtained multi-epoch radial velocity measurements of a representative
sample of 139 massive O-type stars across the Small Magellanic Cloud.
We find that 45% of them show radial velocity variations which
demonstrate that they are members of close binary systems,
predominantly with orbital periods of less than one year. After
correcting for observational biases, we find that at least
0.70+0.11-0.06 of the O stars in our sample are in close
binaries, and that at least 68+7-8% of all O stars will interact
with a companion star during their lifetime. We found no evidence
supporting a statistically significant trend of the multiplicity
properties with metallicity. Our results indicate that multiplicity
and binary interactions govern the evolution of massive stars and
determine their cosmic feedback and explosive fates, which has strong
implications for our understanding of the high redshift Universe.
Description:
Journal of the observations and radial velocity measurements
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
stars.dat 35 139 List of studied stars
table1.dat 36 1234 Radial velocity measurements
table2.dat 47 80 Journal of the observations
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See also:
J/A+A/690/A289 : Binarity at LOw Metallicity (BLOeM). I. (Shenar+, 2024)
Byte-by-byte Description of file: stars.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Object BLOeM identifier (BLOeM_N-NNN)
13- 22 F10.7 deg RAdeg Right ascension (J2000)
24- 35 F12.8 deg DEdeg Declination (J2000)
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Object BLOeM identifier (BLOeM_N-NNN)
14- 22 F9.3 d MJD Modified Julian Data at mid-exposure
26- 30 F5.1 km/s RV Radial Velocity
33- 36 F4.1 km/s e_RV Uncertainty on the radial Velocity
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Object BLOeM identifier (BLOeM_N-NNN)
15- 16 I2 --- Npairs Number of RV pairs that pass the 4-sigma
variability criterion with large (SB) or
small (RVvar) RV variation amplitudes
19- 23 F5.1 --- Signi Significance of the RV variation
27- 31 F5.1 km/s deltaRV Maximum RV variations between all pairs that
meet the variability criteria
36- 40 F5.2 d deltat Minimum time difference between all pairs that
meet the variability criteria
43- 47 A5 --- Status Binary/Variability status (SB or RVvar)
--------------------------------------------------------------------------------
History:
From Hugues Sana, hugues.sana(at)kuleuven.be
Acknowledgements:
Based on data collected at the European Southern Observatory (ESO)
under program ID 112.25R7. The research leading to these results has
received funding from the European Research Council (ERC) under the
European Union's Horizon 2020 and Horizon Europe research and
innovation programme (grant agreement numbers 772225: MULTIPLES,
772086: ASSESS and 945806: TEL-STARS, ADG101054731:
Stellar-BHs-SDSS-V, and 101164755: METAL). This research was supported
by the Israel Science Foundation (ISF) under grant number 0603225041.
The authors acknowledge support from the Science and Technology
Facilities Council (research grant ST/V000853/1 and ST/V000233/1), UK
Research and Innovation (UKRI) and the UK government's ERC Horizon
Europe funding guarantee (grant number: EP/Y031059/1), a Royal Society
University Research Fellowship (grant number: URF/R1/231631), a Royal
Society--Science Foundation Ireland University Research Fellowship,
the German Deutsche Forschungsgemeinschaft (Project-ID 496854903,
445674056, and 443790621, Germany's Excellence Strategy EXC
2181/1-390900948), the Klaus Tschira Foundation, the JSPS Kakenhi
Grant-in-Aid for Scientific Research (23K19071), the Australian
Research Council (ARC) Centre of Excellence for Gravitational Wave
Discovery (OzGrav; project number CE230100016), the Deutsches Zentrum
fur Luft und Raumfahrt (DLR) grants FKZ 50OR2005 and 50OR2306, Agencia
Espanola de Investigacion (AEI) of the Spanish Ministerio de Ciencia
Innovacion y Universidades (MICIU) and the European Regional
Development Fund, FEDER and Severo Ochoa Programme (grants
PID2021-122397NB-C21 and CEX2019-000920-S), the NextGeneration EU/PRTR
and MIU (UNI/551/2021) trough grant Margarita Salas-UL, the CAPES-Br
and FAPERJ/DSC-10 (SEI-260003/001630/2023),
MCIN/AEI/10.13039/501100011033 by "ERDF A way of making Europe"
(grants PID2019-105552RB-C41 and PID2022-137779OB-C41,
PID2021-125485NB-C22, CEX2019-000918-M) funded by
MCIN/AEI/10.13039/501100011033 (State Agency for Research of the
Spanish Ministry of Science and Innovation) and SGR-2021-01069
(AGAUR), the Spanish Government Ministerio de Ciencia e Innovacion and
Agencia Estatal de Investigacion (10.13 039/501 100 011 033; grant
PID2022-136 640 NB-C22), the Consejo Superior de Investigaciones
Cientificas (CSIC; grant 2022-AEP∼005), the Polish National Agency
for Academic Exchange (BEKKER fellowship BPN/BEK/2022/1/00106) and
National Science Center (NCN, Poland; grant number OPUS
2021/41/B/ST9/00757), the "La Caixa" Foundation (ID 100010434) under
the fellowship code LCF/BQ/PI23/11970035, the Research foundation
Flanders (FWO) PhD fellowship under project 11E1721N and senior
postdoctoral fellowship under number 12ZY523N, and the Netherlands
Research Council NWO (VIDI 203.061 grant).
(End) Patricia Vannier [CDS] 16-May-2025