Conference paper Open Access

Unlocking Galactic Wolf-Rayet stars with Gaia DR2

Rate, Gemma; Crowther, Paul A.

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  "description": "<p>Wolf-Rayet (WR) stars represent the final evolutionary stage of the most massive O stars and can reveal much about<br>\nmassive star origins and fates. We can study their formation and frequency of binary interaction, by measuring<br>\nthe fraction in clusters and associations and identifying runaways far from the Galactic plane. Additionally, their<br>\nabsolute magnitudes and luminosities remain poorly constrained in the Milky Way. Accurate distances to individual<br>\nstars are required to improve our knowledge of WR stars. Past work relied upon absolute magnitude calibrations<br>\nto find distances, with large associated uncertainties. Parallaxes give more precise results and Gaia DR2 (Gaia<br>\nCollaboration et al., 2018) expands the number of WR stars with parallaxes from one star to several hundred. Here<br>\nwe have calculated new distances to 382 WR stars using DR2 astrometry. We also calculate absolute magnitudes for<br>\nstars with distances. 184 are plausible, confirming these stars have reliable distances. Recalculated luminosities are<br>\nfound to be lower than expected, potentially indicating binary interaction or requiring improved single star models.<br>\nWe confirm only a small proportion (13%) of WR stars are definitely members of clusters or associations, implying<br>\nmany WR stars may form in relatively sparse environments. We also search for runaways by applying a vertical<br>\ncutoff distance of 156pc from the Galactic midplane. 31 stars (8%) exceed this distance and so are likely runaways.<br>\nThe low fraction of binary companions, combined with the low frequency of clusters and association membership,<br>\nleads us to conclude that supernovae from close binary companions are the dominant source of runaways.</p>\n\n<p>&nbsp;</p>", 
  "license": "", 
  "creator": [
      "affiliation": "University of Sheffield", 
      "@type": "Person", 
      "name": "Rate, Gemma"
      "affiliation": "University of Sheffield", 
      "@type": "Person", 
      "name": "Crowther, Paul A."
  "headline": "Unlocking Galactic Wolf-Rayet stars with Gaia DR2", 
  "image": "", 
  "datePublished": "2019-05-28", 
  "url": "", 
  "version": "1", 
  "@type": "ScholarlyArticle", 
  "@context": "", 
  "identifier": "", 
  "@id": "", 
  "workFeatured": {
    "url": "", 
    "location": "ESTEC (Noordwijk, The Netherlands)", 
    "@type": "Event", 
    "name": "53rd ESLAB symposium: the Gaia universe"
  "name": "Unlocking Galactic Wolf-Rayet stars with Gaia DR2"
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