Spectra of a rare low-mass Wolf-Rayet star in LMC Virtual Observatory Resource

Authors
  1. Margon B.
  2. Manea C.
  3. Williams R.
  4. Bond H.E.
  5. Prochaska J.X.,Szymanski M.K.
  6. Morrell N.
  7. Published by
    CDS
Abstract

We report the serendipitous discovery of an object, UVQSJ060819.93-715737.4, with a spectrum dominated by extremely intense, narrow CII emission lines. The spectrum is similar to those of the very rare, late-type [WC11] low-mass Wolf-Rayet stars. Despite the recognition of these stars as a distinct class decades ago, there remains barely a handful of Galactic members, all of which are also planetary-nebula central stars. Although no obvious surrounding nebulosity is present in J0608, [OII], [NII], and [SII] emission suggest the presence of an inconspicuous, low-excitation nebula. There is low-amplitude incoherent photometric variability on timescales of days to years, as well as numerous prominent P Cygni profiles, implying mass loss. There are indications of a binary companion. The star is located on the outskirts of the LMC, and the observed radial velocity (~+250km/s) and proper motion strongly suggest membership. If indeed an LMC member, this is the first extragalactic late [WC] star, and the first with an accurately determined luminosity, as the Galactic examples are too distant for precise parallax determinations. A high-quality, broad-coverage spectrum of the prototype of the late [WC] class, CPD -56 8032, is also presented. We discuss different excitation mechanisms capable of producing the great strength of the CII emission. Numerous autoionizing levels of C II are definitely populated by processes other than dielectronic recombination. Despite the spectacular emission spectra, observational selection makes objects such as these difficult to discover. Members of the [WC11] class may in fact be considerably more common than the handful of previously known late [WC] stars.

Keywords
  1. wolf-rayet-stars
  2. magellanic-clouds
  3. visible-astronomy
  4. spectroscopy
  5. infrared-astronomy
  6. radial-velocity
  7. line-intensities
Bibliographic source Bibcode
2020ApJ...888...54M
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/888/54
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/888/54
Document Object Identifer DOI
doi:10.26093/cds/vizier.18880054

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http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/888/54
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History

2021-07-13T14:50:54Z
Resource record created
2021-07-13T14:50:54Z
Created
2021-10-25T10:12:43Z
Updated

Contact

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