{
  "id": "1911.07032",
  "version": "v1",
  "published": "2019-11-16T13:45:38.000Z",
  "updated": "2019-11-16T13:45:38.000Z",
  "title": "Two New Rapidly-Rotating ON Stars Found With LAMOST",
  "authors": [
    "Guang-Wei Li",
    "Ian D. Howarth"
  ],
  "comment": "8 pages, 4 figures, 2 tables",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "The ON stars are a rare subtype of O stars, of uncertain origin. We report two new, rapidly-rotating ON stars found in data acquired with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST. LS I +61 28 is an ON8.5 Vn dwarf with a projected equatorial rotational velocity of $v_{\\textrm e}\\sin{i} \\simeq 298$ km$\\;$s$^{-1}$, while HDE 236672 is an ON9 IVn subgiant with $v_{\\textrm e}\\sin{i} \\simeq 253$ km$\\;$s$^{-1}$ The former is the first rapidly-rotating ON dwarf to be found, and the latter is only the third ON subgiant. The luminosity classes of non-supergiant ON stars appear to be influenced by the axial inclination angle $i$: the rapidly-rotating giants are close to equator-on, while ON dwarfs with lower $v_{\\textrm e}\\sin{i}$ values are viewed more nearly pole-on. Combining parallaxes and proper motions from Gaia DR2 with radial-velocity measurements, we investigate the kinematics of non-supergiant ON stars, and infer that the dynamics, rapid rotation, and surface-nitrogen characteristics may all be consequences of binary interaction.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-11-16T13:45:38.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "area multi-object fiber spectroscopic telescope",
      "large sky area multi-object fiber",
      "sky area multi-object fiber spectroscopic",
      "rapidly-rotating",
      "projected equatorial rotational velocity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}