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| Paper: |
An Evolutionary Model for the Massive Black Hole X-Ray Binary M33 X-7. |
| Volume: |
447, Evolution of Compact Binaries |
| Page: |
271 |
| Authors: |
Valsecchi, F.; Glebbeek, E.; Farr, W. M.; Fragos, T.; Willems, B.; Orosz, J. A.; Liu, J.; Kalogera, V. |
| Abstract: |
Black hole (BH) X-ray binaries (XRBs) are X-ray bright binary systems
comprising a BH accreting matter from a companion star.
Unravelling the evolutionary history of observed XRBs can shed light on how
BHs form, evolve and interact with their host environment, processes that
yet lack a conclusive physical explanation. Our focus here lies on M33 X-7,
which is among the heaviest BH XRBs known to date, hosting a 15.65 M☉ BH orbiting a 70 M☉ companion star in a
3.45 day orbit. The high masses of the binary components and the tight
orbit present a challenge for typically invoked BH-XRBs formation channels.
The picture is further complicated by the measured underluminosity of the
stellar component.
Here we propose the first evolutionary scenario for M33 X-7 that is consistent
with the complete set of current observational constraints.
According to our model, the progenitors of M33 X-7 are constrained to host
primaries and secondaries between 85–99 M☉ and 28–32 M☉,
respectively, and initial orbital periods between 2.8–3.1 days. In order
to form a BH of 15.65 M☉, the BH progenitor transferred part of
its envelope to the companion star and lost the rest in a strong stellar wind.
During this dynamically stable mass transfer phase the companion accreted
matter, to become the presently underluminous 70 M☉ star. |
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