article published yes L. R. Patrick author D. J. Lennon author F. Najarro author T. Shenar author J. Bodensteiner author H. Sana author P. A. Crowther author N. Britavskiy author N. Langer author A. Schootemeijer author C. J. Evans author L. Mahy author Ylva Louise Linsdotter Götberg author d0648d0c-0f64-11ee-a2e0-dd0faa2e4f7d0000-0002-6960-6911 S. E. De Mink author F. R.N. Schneider author A. J.G. O’Grady author J. I. Villaseñor author M. Bernini-Peron author D. M. Bowman author A. De Koter author K. Deshmukh author A. Gilkis author G. González-Torà author V. M. Kalari author Z. K̃Eszthelyi author I. Mandel author A. Menon author M. Moe author L. M. Oskinova author D. Pauli author M. Renzo author A. A.C. Sander author K. Sen author M. Stoop author J. T. Van Loon author S. Toonen author F. Tramper author J. S. Vink author C. Wang author YlGo department Given the uncertain evolutionary status of blue supergiant stars, their multiplicity properties hold vital clues to better understand their origin and evolution. As part of The Binarity at LOw Metallicity (BLOeM) campaign in the Small Magellanic Cloud, we present a multi-epoch spectroscopic survey of 128 supergiant stars of spectral type B5–F5, which roughly correspond to initial masses in the 6–30 M⊙ range. The observed binary fraction for the B5–9 supergiants is 25 ± 6% (10 ± 4%) and 5 ± 2% (0%) for the A–F stars, which were found using a radial-velocity (RV) variability threshold of 5 km s−1 (10 km s−1) as a criterion for binarity. Accounting for observational biases, we find an intrinsic multiplicity fraction of less than 18% for the B5–9 stars and 8−7+9% for the AF stars, for the orbital periods up to 103.5 days and mass ratios (q) in the 0.1 < q < 1 range. The large stellar radii of these supergiant stars prevent short orbital periods, but we demonstrate that this effect alone cannot explain our results. We assessed the spectra and RV time series of the detected binary systems and find that only a small fraction display convincing solutions. We conclude that the multiplicity fractions are compromised by intrinsic stellar variability, such that the true multiplicity fraction may be significantly smaller. Our main conclusions from comparing the multiplicity properties of the B5–9- and AF-type supergiants to that of their less evolved counterparts is that such stars cannot be explained by a direct evolution from the main sequence. Furthermore, by comparing their multiplicity properties to red supergiant stars, we conclude that the AF supergiant stars are neither progenitors nor descendants of red supergiants. https://research-explorer.ista.ac.at/download/19842/19863/2025_AstronomyAstrophysics_Patrick.pdf application/pdfno EDP Sciences2025 eng 0004-6361 1432-0746 2502.02644 00149790310002810.1051/0004-6361/202452949 698 L.R. Patrick, D.J. Lennon, F. Najarro, T. Shenar, J. Bodensteiner, H. Sana, P.A. Crowther, N. Britavskiy, N. Langer, A. Schootemeijer, C.J. Evans, L. Mahy, Y.L.L. Götberg, S.E. De Mink, F.R.N. Schneider, A.J.G. O’Grady, J.I. Villaseñor, M. Bernini-Peron, D.M. Bowman, A. De Koter, K. Deshmukh, A. Gilkis, G. González-Torà, V.M. Kalari, Z. K̃Eszthelyi, I. Mandel, A. Menon, M. Moe, L.M. Oskinova, D. Pauli, M. Renzo, A.A.C. Sander, K. Sen, M. Stoop, J.T. Van Loon, S. Toonen, F. Tramper, J.S. Vink, C. Wang, Astronomy &#38; Astrophysics 698 (2025). Patrick, L. R., et al. “Binarity at LOw Metallicity (BLOeM): The Multiplicity Properties and Evolution of BAF-Type Supergiants.” <i>Astronomy &#38; Astrophysics</i>, vol. 698, A39, EDP Sciences, 2025, doi:<a href="https://doi.org/10.1051/0004-6361/202452949">10.1051/0004-6361/202452949</a>. L. R. Patrick <i>et al.</i>, “Binarity at LOw Metallicity (BLOeM): The multiplicity properties and evolution of BAF-type supergiants,” <i>Astronomy &#38; Astrophysics</i>, vol. 698. EDP Sciences, 2025. Patrick LR, Lennon DJ, Najarro F, et al. Binarity at LOw Metallicity (BLOeM): The multiplicity properties and evolution of BAF-type supergiants. <i>Astronomy &#38; Astrophysics</i>. 2025;698. doi:<a href="https://doi.org/10.1051/0004-6361/202452949">10.1051/0004-6361/202452949</a> Patrick LR, Lennon DJ, Najarro F, Shenar T, Bodensteiner J, Sana H, Crowther PA, Britavskiy N, Langer N, Schootemeijer A, Evans CJ, Mahy L, Götberg YLL, De Mink SE, Schneider FRN, O’Grady AJG, Villaseñor JI, Bernini-Peron M, Bowman DM, De Koter A, Deshmukh K, Gilkis A, González-Torà G, Kalari VM, K̃Eszthelyi Z, Mandel I, Menon A, Moe M, Oskinova LM, Pauli D, Renzo M, Sander AAC, Sen K, Stoop M, Van Loon JT, Toonen S, Tramper F, Vink JS, Wang C. 2025. Binarity at LOw Metallicity (BLOeM): The multiplicity properties and evolution of BAF-type supergiants. Astronomy &#38; Astrophysics. 698, A39. Patrick, L. R., Lennon, D. J., Najarro, F., Shenar, T., Bodensteiner, J., Sana, H., … Wang, C. (2025). Binarity at LOw Metallicity (BLOeM): The multiplicity properties and evolution of BAF-type supergiants. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202452949">https://doi.org/10.1051/0004-6361/202452949</a> Patrick, L. R., D. J. Lennon, F. Najarro, T. Shenar, J. Bodensteiner, H. Sana, P. A. Crowther, et al. “Binarity at LOw Metallicity (BLOeM): The Multiplicity Properties and Evolution of BAF-Type Supergiants.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2025. <a href="https://doi.org/10.1051/0004-6361/202452949">https://doi.org/10.1051/0004-6361/202452949</a>. 198422025-06-15T22:01:29Z2026-02-16T12:09:50Z