A Roche lobe-filling hot subdwarf and white dwarf binary: possible detection of an ejected common envelope
| العنوان: | A Roche lobe-filling hot subdwarf and white dwarf binary: possible detection of an ejected common envelope |
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| المؤلفون: | Jiangdan Li, Christopher A Onken, Christian Wolf, Péter Németh, Mike Bessell, Zhenwei Li, Xiaobin Zhang, Jiao Li, Luqian Wang, Lifang Li, Yangping Luo, Hailiang Chen, Kaifan Ji, Xuefei Chen, Zhanwen Han |
| المصدر: | Monthly Notices of the Royal Astronomical Society. 515:3370-3382 |
| بيانات النشر: | Oxford University Press (OUP), 2022. |
| سنة النشر: | 2022 |
| مصطلحات موضوعية: | High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Solar and Stellar Astrophysics (astro-ph.SR) |
| الوصف: | Binaries consisting of a hot subdwarf star and an accreting white dwarf (WD) are sources of gravitational wave radiation at low frequencies and possible progenitors of type Ia supernovae if the WD mass is large enough. Here, we report the discovery of the third binary known of this kind: it consists of a hot subdwarf O (sdO) star and a WD with an orbital period of 3.495 hours and an orbital shrinkage of 0.1 s in 6 yr. The sdO star overfills its Roche lobe and likely transfers mass to the WD via an accretion disk. From spectroscopy, we obtain an effective temperature of $T_{\mathrm{eff}}=54\,240\pm1\,840$ K and a surface gravity of $\log{g}=4.841\pm0.108$ for the sdO star. From the light curve analysis, we obtain a sdO mass of $M_{\mathrm{sdO}}=0.55$ ${\mathrm{M_{\odot}}}$ and a mass ratio of $q=M_{\mathrm{WD}}/M_{\mathrm{sdO}}=0.738\pm0.001$. Also, we estimate that the disk has a radius of $\sim 0.41R_\odot$ and a thickness of $\sim 0.18R_\odot$. The origin of this binary is probably a common envelope ejection channel, where the progenitor of the sdO star is either an RGB star or, more likely, an early AGB star; the sdO star will subsequently evolve into a WD and merge with its WD companion, likely resulting in an R CrB star. The outstanding feature in the spectrum of this object is strong Ca H&K lines, which are blueshifted by $\sim$200 km/s and likely originate from the recently ejected common envelope, and we estimated that the remnant CE material in the binary system has a density $\sim 6\times 10^{-10} {\rm g/cm^3}$. 13 pages, 15 figures, to be published in MNRAS |
| تدمد: | 1365-2966 0035-8711 |
| DOI: | 10.1093/mnras/stac1768 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::15963dc8d6d7ec7813b2a49143d4d44a https://doi.org/10.1093/mnras/stac1768 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....15963dc8d6d7ec7813b2a49143d4d44a |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 13652966 00358711 |
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| DOI: | 10.1093/mnras/stac1768 |