View in EDS PDF Full Text

A Be-type star with a black-hole companion.

Saved in:
Bibliographic Details
Title: A Be-type star with a black-hole companion.
Authors: Casares, J., Negueruela, I., Ribó, M., Ribas, I., Paredes, J. M., Herrero, A., Simón-Díaz, S.
Source: Nature. 1/16/2014, Vol. 505 Issue 7483, p378-381. 4p.
Subjects: Stellar mass, Black holes, Be stars, Accretion in galactic x-ray sources, Binary stars, Neutron stars, Accretion disks
Abstract: Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen). Of the approximately 80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as companions. A black hole was formally allowed as a solution for the companion to the Be star MWC 656 (ref. 5; also known as HD 215227), although that conclusion was based on a single radial velocity curve of the Be star, a mistaken spectral classification and rough estimates of the inclination angle. Here we report observations of an accretion disk line mirroring the orbit of MWC 656. This, together with an improved radial velocity curve of the Be star through fitting sharp Fe ii profiles from the equatorial disk, and a refined Be classification (to that of a B1.5-B2 III star), indicates that a black hole of 3.8 to 6.9 solar masses orbits MWC 656, the candidate counterpart of the γ-ray source AGL J2241+4454 (refs 5, 6). The black hole is X-ray quiescent and fed by a radiatively inefficient accretion flow giving a luminosity less than 1.6 × 10−7 times the Eddington luminosity. This implies that Be binaries with black-hole companions are difficult to detect in conventional X-ray surveys. [ABSTRACT FROM AUTHOR]
Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Psychology and Behavioral Sciences Collection
FullText Links:
  – Type: pdflink
Text:
  Availability: 0
Header DbId: pbh
DbLabel: Psychology and Behavioral Sciences Collection
An: 93707420
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: A Be-type star with a black-hole companion.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Casares%2C+J%2E%22">Casares, J.</searchLink><br /><searchLink fieldCode="AR" term="%22Negueruela%2C+I%2E%22">Negueruela, I.</searchLink><br /><searchLink fieldCode="AR" term="%22Ribó%2C+M%2E%22">Ribó, M.</searchLink><br /><searchLink fieldCode="AR" term="%22Ribas%2C+I%2E%22">Ribas, I.</searchLink><br /><searchLink fieldCode="AR" term="%22Paredes%2C+J%2E+M%2E%22">Paredes, J. M.</searchLink><br /><searchLink fieldCode="AR" term="%22Herrero%2C+A%2E%22">Herrero, A.</searchLink><br /><searchLink fieldCode="AR" term="%22Simón-Díaz%2C+S%2E%22">Simón-Díaz, S.</searchLink>
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Nature%22">Nature</searchLink>. 1/16/2014, Vol. 505 Issue 7483, p378-381. 4p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Stellar+mass%22">Stellar mass</searchLink><br /><searchLink fieldCode="DE" term="%22Black+holes%22">Black holes</searchLink><br /><searchLink fieldCode="DE" term="%22Be+stars%22">Be stars</searchLink><br /><searchLink fieldCode="DE" term="%22Accretion+in+galactic+x-ray+sources%22">Accretion in galactic x-ray sources</searchLink><br /><searchLink fieldCode="DE" term="%22Binary+stars%22">Binary stars</searchLink><br /><searchLink fieldCode="DE" term="%22Neutron+stars%22">Neutron stars</searchLink><br /><searchLink fieldCode="DE" term="%22Accretion+disks%22">Accretion disks</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen). Of the approximately 80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as companions. A black hole was formally allowed as a solution for the companion to the Be star MWC 656 (ref. 5; also known as HD 215227), although that conclusion was based on a single radial velocity curve of the Be star, a mistaken spectral classification and rough estimates of the inclination angle. Here we report observations of an accretion disk line mirroring the orbit of MWC 656. This, together with an improved radial velocity curve of the Be star through fitting sharp Fe ii profiles from the equatorial disk, and a refined Be classification (to that of a B1.5-B2 III star), indicates that a black hole of 3.8 to 6.9 solar masses orbits MWC 656, the candidate counterpart of the γ-ray source AGL J2241+4454 (refs 5, 6). The black hole is X-ray quiescent and fed by a radiatively inefficient accretion flow giving a luminosity less than 1.6 × 10−7 times the Eddington luminosity. This implies that Be binaries with black-hole companions are difficult to detect in conventional X-ray surveys. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Nature is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=pbh&AN=93707420
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1038/nature12916
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 4
        StartPage: 378
    Subjects:
      – SubjectFull: Stellar mass
        Type: general
      – SubjectFull: Black holes
        Type: general
      – SubjectFull: Be stars
        Type: general
      – SubjectFull: Accretion in galactic x-ray sources
        Type: general
      – SubjectFull: Binary stars
        Type: general
      – SubjectFull: Neutron stars
        Type: general
      – SubjectFull: Accretion disks
        Type: general
    Titles:
      – TitleFull: A Be-type star with a black-hole companion.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Casares, J.
      – PersonEntity:
          Name:
            NameFull: Negueruela, I.
      – PersonEntity:
          Name:
            NameFull: Ribó, M.
      – PersonEntity:
          Name:
            NameFull: Ribas, I.
      – PersonEntity:
          Name:
            NameFull: Paredes, J. M.
      – PersonEntity:
          Name:
            NameFull: Herrero, A.
      – PersonEntity:
          Name:
            NameFull: Simón-Díaz, S.
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 16
              M: 01
              Text: 1/16/2014
              Type: published
              Y: 2014
          Identifiers:
            – Type: issn-print
              Value: 00280836
          Numbering:
            – Type: volume
              Value: 505
            – Type: issue
              Value: 7483
          Titles:
            – TitleFull: Nature
              Type: main
ResultId 1