VLBA Detections in the Oph-S1 Binary System near Periastron Confirmation of its Orbital Elements and Mass
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| Main Authors: | , , , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866916645299027968 |
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| author | Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Galli, Phillip A. B. Masqué, Josep M. Dupuy, Trent J. Quiroga-Nuñez, Luis H. Rodríguez, Luis F. |
| author_facet | Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Galli, Phillip A. B. Masqué, Josep M. Dupuy, Trent J. Quiroga-Nuñez, Luis H. Rodríguez, Luis F. |
| contents | Oph-S1 is the most luminous and massive stellar member of the nearby Ophiuchus star-forming region. Previous Very Long Baseline Array (VLBA) observations have shown it to be an intermediate-mass binary system ($\sim 5\,{\rm M}_\odot$) with an orbital period of about 21 months, but a paucity of radio detections of the secondary near periastron could potentially have affected the determination of its orbital parameters. Here, we present nine new VLBA observations of Oph-S1 focused on its periastron passage in early 2024. We detect the primary in all observations and the secondary at five epochs, including three within about a month of periastron passage. The updated orbit, determined by combining our new data with 35 previous observations, agrees well with previous calculations and yields masses of $4.115 \pm0.039 \,{\rm M}_\odot$ and $0.814\pm0.006 \,{\rm M}_\odot$ for the two stars in the system. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2503_04594 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | VLBA Detections in the Oph-S1 Binary System near Periastron Confirmation of its Orbital Elements and Mass Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Galli, Phillip A. B. Masqué, Josep M. Dupuy, Trent J. Quiroga-Nuñez, Luis H. Rodríguez, Luis F. Solar and Stellar Astrophysics Oph-S1 is the most luminous and massive stellar member of the nearby Ophiuchus star-forming region. Previous Very Long Baseline Array (VLBA) observations have shown it to be an intermediate-mass binary system ($\sim 5\,{\rm M}_\odot$) with an orbital period of about 21 months, but a paucity of radio detections of the secondary near periastron could potentially have affected the determination of its orbital parameters. Here, we present nine new VLBA observations of Oph-S1 focused on its periastron passage in early 2024. We detect the primary in all observations and the secondary at five epochs, including three within about a month of periastron passage. The updated orbit, determined by combining our new data with 35 previous observations, agrees well with previous calculations and yields masses of $4.115 \pm0.039 \,{\rm M}_\odot$ and $0.814\pm0.006 \,{\rm M}_\odot$ for the two stars in the system. |
| title | VLBA Detections in the Oph-S1 Binary System near Periastron Confirmation of its Orbital Elements and Mass |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2503.04594 |