Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray Binaries
We examine the proposal that the subset of neutron-star and black-hole X-ray binaries that form with Ap or Bp star companions will experience systemic angular-momentum losses due to magnetic braking, not otherwise operative with intermediate-mass companion stars. We suggest that for donor stars poss...
| Main Authors: | , , |
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| 格式: | Journal article |
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2005
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| _version_ | 1826304745394929664 |
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| author | Justham, S Rappaport, S Podsiadlowski, P |
| author_facet | Justham, S Rappaport, S Podsiadlowski, P |
| author_sort | Justham, S |
| collection | OXFORD |
| description | We examine the proposal that the subset of neutron-star and black-hole X-ray binaries that form with Ap or Bp star companions will experience systemic angular-momentum losses due to magnetic braking, not otherwise operative with intermediate-mass companion stars. We suggest that for donor stars possessing the anomalously high magnetic fields associated with Ap and Bp stars, a magnetically coupled, irradiation-driven stellar wind can lead to substantial systemic loss of angular-momentum. In this paper we apply this mechanism to a specific astrophysics problem involving the formation of compact black-hole binaries with low-mass donor stars. At present, it is not understood how these systems form, given that low-mass companion stars are not likely to provide sufficient gravitational potential to unbind the envelope of the massive progenitor of the black hole during a prior `common-envelope' phase. However, in the absence of magnetic braking, such systems tend to evolve to long orbital periods. We show that, with the proposed magnetic braking properties afforded by Ap and Bp companions, such a scenario can lead to the formation of compact black-hole binaries with orbital periods, donor masses, lifetimes, and production rates that are in accord with the observations. In spite of these successes, our models reveal a significant discrepancy between the calculated effective temperatures and the observed spectral types of the donor stars. Finally, we show that this temperature discrepancy would still exist for other scenarios invoking initially intermediate-mass donor stars, and this presents a substantial unresolved mystery. |
| first_indexed | 2024-03-07T06:22:27Z |
| format | Journal article |
| id | oxford-uuid:f3262bc0-7d6c-47e3-940c-e0cf4a67342f |
| institution | University of Oxford |
| last_indexed | 2024-03-07T06:22:27Z |
| publishDate | 2005 |
| record_format | dspace |
| spelling | oxford-uuid:f3262bc0-7d6c-47e3-940c-e0cf4a67342f2022-03-27T12:09:43ZMagnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray BinariesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f3262bc0-7d6c-47e3-940c-e0cf4a67342fSymplectic Elements at Oxford2005Justham, SRappaport, SPodsiadlowski, PWe examine the proposal that the subset of neutron-star and black-hole X-ray binaries that form with Ap or Bp star companions will experience systemic angular-momentum losses due to magnetic braking, not otherwise operative with intermediate-mass companion stars. We suggest that for donor stars possessing the anomalously high magnetic fields associated with Ap and Bp stars, a magnetically coupled, irradiation-driven stellar wind can lead to substantial systemic loss of angular-momentum. In this paper we apply this mechanism to a specific astrophysics problem involving the formation of compact black-hole binaries with low-mass donor stars. At present, it is not understood how these systems form, given that low-mass companion stars are not likely to provide sufficient gravitational potential to unbind the envelope of the massive progenitor of the black hole during a prior `common-envelope' phase. However, in the absence of magnetic braking, such systems tend to evolve to long orbital periods. We show that, with the proposed magnetic braking properties afforded by Ap and Bp companions, such a scenario can lead to the formation of compact black-hole binaries with orbital periods, donor masses, lifetimes, and production rates that are in accord with the observations. In spite of these successes, our models reveal a significant discrepancy between the calculated effective temperatures and the observed spectral types of the donor stars. Finally, we show that this temperature discrepancy would still exist for other scenarios invoking initially intermediate-mass donor stars, and this presents a substantial unresolved mystery. |
| spellingShingle | Justham, S Rappaport, S Podsiadlowski, P Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray Binaries |
| title | Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
Binaries |
| title_full | Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
Binaries |
| title_fullStr | Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
Binaries |
| title_full_unstemmed | Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
Binaries |
| title_short | Magnetic Braking of Ap/Bp Stars: Application to Compact Black-Hole X-Ray
Binaries |
| title_sort | magnetic braking of ap bp stars application to compact black hole x ray binaries |
| work_keys_str_mv | AT justhams magneticbrakingofapbpstarsapplicationtocompactblackholexraybinaries AT rappaports magneticbrakingofapbpstarsapplicationtocompactblackholexraybinaries AT podsiadlowskip magneticbrakingofapbpstarsapplicationtocompactblackholexraybinaries |