NIR spectral classification of the companion in the gamma-ray binary HESS J1832-093 as an O6 V star
HESS J1832−093 is a member of the rare class of gamma-ray binaries, as recently confirmed by the detection of orbitally modulated X-ray and gamma-ray emission with a period of ∼86 d. The spectral type of the massive companion star has been difficult to retrieve as there is no optical counterpart, bu...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/357620 |
| Acceso en línea: | http://hdl.handle.net/10261/357620 |
| Access Level: | acceso abierto |
| Palabra clave: | Binaries: spectroscopic Stars: neutron Gamma-rays: stars X-rays: binaries X-rays: individual: (HESS J1832−093, 2MASS J18324516−0921545) |
| Sumario: | HESS J1832−093 is a member of the rare class of gamma-ray binaries, as recently confirmed by the detection of orbitally modulated X-ray and gamma-ray emission with a period of ∼86 d. The spectral type of the massive companion star has been difficult to retrieve as there is no optical counterpart, but the system is coincident with a near-infrared source. Previous results have shown that the infrared counterpart is consistent with an O or B-type star, but a clear classification is still lacking. We observed the counterpart twice, in 2019 and 2021, with the X-Shooter spectrograph operating on the Very Large Telescope (VLT). The obtained spectra classify the counterpart as an O6 V-type star. We estimate a distance to the source of 6.7 ± 0.5 kpc, although this estimate can be severely affected by the high extinction towards the source. This new O6 V classification for the companion star in HESS J1832−093 provides further support to an apparent grouping around a given spectral type for all discovered gamma-ray binaries that contain an O-type star. This may be due to the interplay between the initial mass function and the wind momentum–luminosity relation. |
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