Confirmation of the First Helium Star Stripped by a Black Hole
Abstract
In a search for stars stripped of their H-rich envelopes in binaries, we have discovered a candidate stripped star - black hole (BH) system. The star appears to be an isolated, ~8Msun, helium star but radial velocities reveals an orbit of 75 days, suggesting a companion mass of >2.2 Msun. With no signs of the presence of a main sequence star in the optical spectrum, it is likely this dark companion is a BH. If true, this system would be the first discovered in a population of X-ray faint BH X-ray binaries with helium-rich donors, yielding legacy value. They are also expected to be progenitors of merging compact objects with extreme mass ratio, such as NSBH systems or the gravitational wave event GW190814. A 50ks deep Chandra exposure will reveal the true nature of this dark companion.
- Publication:
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Chandra Proposal
- Pub Date:
- September 2022
- Bibcode:
- 2022cxo..prop.6307L
- Keywords:
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- Chandra Proposal ID #24400430