Dynamical mass of the Ophiuchus intermediate-mass stellar system S1 with DYNAMO-VLBA
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| Autores principales: | , , , , , , , , , , |
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| Formato: | Preprint |
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2024
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| author | Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Masqué, Josep M. Medina, S. -N. X. Galli, Phillip A. B. Dupuy, Trent J. Rodríguez, Luis F. Quiroga-Nuñez, Luis H. |
| author_facet | Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Masqué, Josep M. Medina, S. -N. X. Galli, Phillip A. B. Dupuy, Trent J. Rodríguez, Luis F. Quiroga-Nuñez, Luis H. |
| contents | We report dynamical mass measurements of the individual stars in the most luminous and massive stellar member of the nearby Ophiuchus star-forming region, the young tight binary system S1. We combine 28 archival datasets with seven recent, proprietary VLBA observations obtained as part of the \textit{Dynamical Masses of Young Stellar Multiple Systems with the VLBA} project (DYNAMO--VLBA), to constrain the astrometric and orbital parameters of the system, and recover high accuracy dynamical masses. The primary component, S1A, is found to have a mass of 4.11$\pm$0.10~M$_\odot$, significantly less than the typical value, $\sim$~6~M$_\odot$ previously reported in the literature. We show that the spectral energy distribution of S1A can be reproduced by a reddened blackbody with a temperature between roughly 14,000~K and 17,000~K. According to evolutionary models, this temperature range corresponds to stellar masses between 4~M$_\odot$ and 6~M$_\odot$ so the SED is not a priori inconsistent with the dynamical mass of S1A. The luminosity of S1 derived from SED-fitting, however, is only consistent with models for stellar masses above 5~M$_\odot$. Thus, we cannot reconcile the evolutionary models with the dynamical mass measurement of S1A: the models consistent with the location of S1A in the HR diagram correspond to masses at least 25\% higher than the dynamical mass. For the secondary component, S1B, a mass of 0.831~$\pm$~0.014~M$_\odot $ is determined, consistent with a low-mass young star. While the radio flux of S1A remains roughly constant throughout the orbit, the flux of S1B is found to be higher near the apastron. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_02885 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Dynamical mass of the Ophiuchus intermediate-mass stellar system S1 with DYNAMO-VLBA Ordóñez-Toro, Jazmín Dzib, Sergio A. Loinard, Laurent Ortiz-León, Gisela Kounkel, Marina A. Masqué, Josep M. Medina, S. -N. X. Galli, Phillip A. B. Dupuy, Trent J. Rodríguez, Luis F. Quiroga-Nuñez, Luis H. Solar and Stellar Astrophysics We report dynamical mass measurements of the individual stars in the most luminous and massive stellar member of the nearby Ophiuchus star-forming region, the young tight binary system S1. We combine 28 archival datasets with seven recent, proprietary VLBA observations obtained as part of the \textit{Dynamical Masses of Young Stellar Multiple Systems with the VLBA} project (DYNAMO--VLBA), to constrain the astrometric and orbital parameters of the system, and recover high accuracy dynamical masses. The primary component, S1A, is found to have a mass of 4.11$\pm$0.10~M$_\odot$, significantly less than the typical value, $\sim$~6~M$_\odot$ previously reported in the literature. We show that the spectral energy distribution of S1A can be reproduced by a reddened blackbody with a temperature between roughly 14,000~K and 17,000~K. According to evolutionary models, this temperature range corresponds to stellar masses between 4~M$_\odot$ and 6~M$_\odot$ so the SED is not a priori inconsistent with the dynamical mass of S1A. The luminosity of S1 derived from SED-fitting, however, is only consistent with models for stellar masses above 5~M$_\odot$. Thus, we cannot reconcile the evolutionary models with the dynamical mass measurement of S1A: the models consistent with the location of S1A in the HR diagram correspond to masses at least 25\% higher than the dynamical mass. For the secondary component, S1B, a mass of 0.831~$\pm$~0.014~M$_\odot $ is determined, consistent with a low-mass young star. While the radio flux of S1A remains roughly constant throughout the orbit, the flux of S1B is found to be higher near the apastron. |
| title | Dynamical mass of the Ophiuchus intermediate-mass stellar system S1 with DYNAMO-VLBA |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2401.02885 |