Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245
In this paper, we constrain the properties of an overluminous blue supergiant star (BSG) in the open cluster vdBH 245. We confirm the cluster membership of a sample of early-to-mid B-type stars using their proper motions, parallaxes, and radial velocities. We measure the stellar parameters through a...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc90d |
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| author | Alexandre Legault Nicole St-Louis André-Nicolas Chené Fabrice Martins Anthony Hervé Leigh C. Smith Karla Peña Ramírez Sebastian Ramírez Alegría Kaimi Kahihikolo |
| author_facet | Alexandre Legault Nicole St-Louis André-Nicolas Chené Fabrice Martins Anthony Hervé Leigh C. Smith Karla Peña Ramírez Sebastian Ramírez Alegría Kaimi Kahihikolo |
| author_sort | Alexandre Legault |
| collection | DOAJ |
| description | In this paper, we constrain the properties of an overluminous blue supergiant star (BSG) in the open cluster vdBH 245. We confirm the cluster membership of a sample of early-to-mid B-type stars using their proper motions, parallaxes, and radial velocities. We measure the stellar parameters through a spectrophotometric analysis of their optical spectra and near-infrared photometry. We correct for the effects of extinction of the cluster’s light and estimate a most likely age range for vdBH 245 of 31.6 ${}_{-13.8}^{+13.1}$ Myr using the Binary Population and Spectral Synthesis (or BPASS) Python software hoki and models from the Geneva group. We find a distance of 2.0 ± 0.2 kpc for the cluster, consistent with the value estimated by Gaia of 2.6 ± 0.5 kpc. However, the new age estimate does not agree with previous studies that have found much younger ages. We find that single-star evolution alone is unable to explain the BSG in that age range, even when considering the impact of rotation on stellar evolution. Instead, we find that the overluminous B8–B9 Ia BSG could be interpreted as a merger between two stars with initial masses ranging from 8.5–12.0 M _⊙ and 1.1–10.8 M _⊙ , with a current mass in the range of 13.4–20.6 M _⊙ . The merger would have occurred somewhere between 5.0 and 21.0 Myr after the cluster’s formation. The discovery of such a BSG appearing too young (≈10 Myr in the single-star paradigm) for its population hints at the importance of considering binary interactions to explain the observed population of Galactic BSGs. |
| format | Article |
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| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-5b029499567d4ef5b272bbffb91a2ec62025-08-20T02:32:16ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01985218010.3847/1538-4357/adc90dConstraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245Alexandre Legault0https://orcid.org/0000-0003-2372-9825Nicole St-Louis1https://orcid.org/0000-0003-3890-3400André-Nicolas Chené2https://orcid.org/0000-0002-1115-6559Fabrice Martins3Anthony Hervé4Leigh C. Smith5https://orcid.org/0000-0002-3259-2771Karla Peña Ramírez6Sebastian Ramírez Alegría7Kaimi Kahihikolo8Centre de Recherche en Astrophysique du Québec, Département de physique, Université de Montréal , Complexe des Sciences, Montréal, QC H2V 0B3, Canada; Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA) , Ctra. Torrejón a Ajalvir km 4, E-28850 Torrejón de Ardoz, Spain; Departamento de Física Teórica, Universidad Autónoma de Madrid (UAM) , Campus de Cantoblanco, E-28049 Madrid, SpainCentre de Recherche en Astrophysique du Québec, Département de physique, Université de Montréal , Complexe des Sciences, Montréal, QC H2V 0B3, CanadaNSF’s NOIRLab , 670 N. A’ohoku Place, Hilo, HI 96720, USACNRS LUPM-UMR5299 , Place Eugène Bataillon—CC 072, 34095, Montpellier, FranceGemini Observatory/NSF’s NOIRLab , 670 N. A’ohoku Place, Hilo, HI 96720, USAInstitute of Astronomy, University of Cambridge , Madingley Road, Cambridge, CB3 0HA, UKVera C. Rubin Observatory , Av Juan Cisternas 1500, La Serena, ChileCentro de Astronomía (CITEVA), Universidad de Antofagasta , Av. Angamos 601, Antofagasta, ChileGemini Observatory/NSF’s NOIRLab , 670 N. A’ohoku Place, Hilo, HI 96720, USAIn this paper, we constrain the properties of an overluminous blue supergiant star (BSG) in the open cluster vdBH 245. We confirm the cluster membership of a sample of early-to-mid B-type stars using their proper motions, parallaxes, and radial velocities. We measure the stellar parameters through a spectrophotometric analysis of their optical spectra and near-infrared photometry. We correct for the effects of extinction of the cluster’s light and estimate a most likely age range for vdBH 245 of 31.6 ${}_{-13.8}^{+13.1}$ Myr using the Binary Population and Spectral Synthesis (or BPASS) Python software hoki and models from the Geneva group. We find a distance of 2.0 ± 0.2 kpc for the cluster, consistent with the value estimated by Gaia of 2.6 ± 0.5 kpc. However, the new age estimate does not agree with previous studies that have found much younger ages. We find that single-star evolution alone is unable to explain the BSG in that age range, even when considering the impact of rotation on stellar evolution. Instead, we find that the overluminous B8–B9 Ia BSG could be interpreted as a merger between two stars with initial masses ranging from 8.5–12.0 M _⊙ and 1.1–10.8 M _⊙ , with a current mass in the range of 13.4–20.6 M _⊙ . The merger would have occurred somewhere between 5.0 and 21.0 Myr after the cluster’s formation. The discovery of such a BSG appearing too young (≈10 Myr in the single-star paradigm) for its population hints at the importance of considering binary interactions to explain the observed population of Galactic BSGs.https://doi.org/10.3847/1538-4357/adc90dOpen star clustersB supergiant starsInteracting binary starsStellar mergers |
| spellingShingle | Alexandre Legault Nicole St-Louis André-Nicolas Chené Fabrice Martins Anthony Hervé Leigh C. Smith Karla Peña Ramírez Sebastian Ramírez Alegría Kaimi Kahihikolo Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 The Astrophysical Journal Open star clusters B supergiant stars Interacting binary stars Stellar mergers |
| title | Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 |
| title_full | Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 |
| title_fullStr | Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 |
| title_full_unstemmed | Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 |
| title_short | Constraints on the Evolution of an Overluminous Blue Supergiant from its Parent Open Cluster, vdBH 245 |
| title_sort | constraints on the evolution of an overluminous blue supergiant from its parent open cluster vdbh 245 |
| topic | Open star clusters B supergiant stars Interacting binary stars Stellar mergers |
| url | https://doi.org/10.3847/1538-4357/adc90d |
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