{
  "id": "2006.09135",
  "version": "v1",
  "published": "2020-06-16T13:28:53.000Z",
  "updated": "2020-06-16T13:28:53.000Z",
  "title": "New Chandra spectral measurements of the O supergiant $ζ$ Puppis indicate a surprising increase in the wind mass-loss rate over 18 years",
  "authors": [
    "David H. Cohen",
    "Jiaming Wang",
    "Lamiaa Dakir",
    "Maurice Leutenegger",
    "Veronique Petit",
    "Alexandre David-Uraz"
  ],
  "comment": "Submitted to MNRAS Letters. Comments are welcome",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA",
    "astro-ph.HE"
  ],
  "abstract": "New long Chandra grating observations of the O supergiant $\\zeta$ Pup show not only a brightening in the x-ray emission line flux of a little more than 25 per cent in the 18 years since Chandra's first observing cycle, but also clear evidence of increased wind absorption signatures in its Doppler-broadened x-ray emission line profiles. Model fitting of ten lines in three day-long HETGS datasets taken during August 2018 (Chandra cycle 19) finds a mass-loss rate of $2.68 \\pm 0.12 \\times 10^{-6}$ Msun/yr which is a 50 per cent increase over the value obtained from fitting the cycle 1 data. The increase in the individual emission line fluxes is greater for short-wavelength lines than long-wavelength lines, as would be expected if a uniform increase in line emission is accompanied by an increase in the wavelength-dependent absorption by the cold wind in which the shock-heated plasma is embedded.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-06-16T13:28:53.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "wind mass-loss rate",
      "chandra spectral measurements",
      "x-ray emission line profiles",
      "surprising increase",
      "supergiant"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}