Study of Massive OBA Stars with X-ray Emission
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arXiv
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| Autores principales: | , , , , , |
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| Formato: | Preprint |
| Publicado: |
2026
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| _version_ | 1866910279360577536 |
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| author | Nikolaeva, E. A. Bikmaev, I. F. Irtuganov, E. N. Gilfanov, M. R. Sunyaev, R. A. Medvedev, P. S. |
| author_facet | Nikolaeva, E. A. Bikmaev, I. F. Irtuganov, E. N. Gilfanov, M. R. Sunyaev, R. A. Medvedev, P. S. |
| contents | A study of the physical parameters of a sample of 15 OBA-type stars with detected X-ray emission from the Spektr-RG/eROSITA telescope is presented. While X-ray emission from cool stars (spectral types F-G-K-M) originates in their near-surface regions, namely in the chromosphere and corona, the origin of X-ray emission in OBA stars requires case-by-case analysis since isolated OBA stars are not intrinsic X-ray emitters.
In this work, we derive the fundamental parameters of the stars in our sample, including the effective temperature $T_{\mathrm{eff}}$ and surface gravity $\log g$, based on spectral energy distribution fitting and optical spectroscopy obtained with the 1.5-m Russian-Turkish telescope RTT-150. An additional analysis of the $\mathrm{H}α$ line profiles allows us to identify possible mechanisms responsible for the observed X-ray emission, including non-stationary stellar winds, interactions in circumstellar material, and coronal emission from hidden cool companions.
We find that the X-ray emission in eight stars, with typical luminosities in the range $\log L_{\mathrm{X}} = 28.5$-$30.0$, is most likely associated with hidden late-type companions. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2606_01582 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Study of Massive OBA Stars with X-ray Emission Nikolaeva, E. A. Bikmaev, I. F. Irtuganov, E. N. Gilfanov, M. R. Sunyaev, R. A. Medvedev, P. S. Solar and Stellar Astrophysics High Energy Astrophysical Phenomena A study of the physical parameters of a sample of 15 OBA-type stars with detected X-ray emission from the Spektr-RG/eROSITA telescope is presented. While X-ray emission from cool stars (spectral types F-G-K-M) originates in their near-surface regions, namely in the chromosphere and corona, the origin of X-ray emission in OBA stars requires case-by-case analysis since isolated OBA stars are not intrinsic X-ray emitters. In this work, we derive the fundamental parameters of the stars in our sample, including the effective temperature $T_{\mathrm{eff}}$ and surface gravity $\log g$, based on spectral energy distribution fitting and optical spectroscopy obtained with the 1.5-m Russian-Turkish telescope RTT-150. An additional analysis of the $\mathrm{H}α$ line profiles allows us to identify possible mechanisms responsible for the observed X-ray emission, including non-stationary stellar winds, interactions in circumstellar material, and coronal emission from hidden cool companions. We find that the X-ray emission in eight stars, with typical luminosities in the range $\log L_{\mathrm{X}} = 28.5$-$30.0$, is most likely associated with hidden late-type companions. |
| title | Study of Massive OBA Stars with X-ray Emission |
| topic | Solar and Stellar Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2606.01582 |