{
  "id": "1208.4111",
  "version": "v1",
  "published": "2012-08-20T20:02:06.000Z",
  "updated": "2012-08-20T20:02:06.000Z",
  "title": "On Absorption by Circumstellar Dust, With the Progenitor of SN2012aw as a Case Study",
  "authors": [
    "C. S. Kochanek",
    "R. Khan",
    "X. Dai"
  ],
  "comment": "Submitted to ApJ",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "We use the progenitor of SN2012aw to illustrate the consequences of modeling circumstellar dust using Galactic (interstellar) extinction laws that (1) ignore dust emission in the near-IR and beyond; (2) average over dust compositions, and (3) mis-characterize the optical/UV absorption by assuming that scattered photons are lost to the observer. The primary consequences for the progenitor of SN2012aw are that both the luminosity and the absorption are significantly over-estimated. In particular, the stellar luminosity is most likely in the range 10^4.8 < L/Lsun < 10^5.0 and the star was not extremely massive for a Type IIP progenitor, with M < 15Msun. Given the properties of the circumstellar dust and the early X-ray/radio detections of SN2012aw, the star was probably obscured by an on-going wind with Mdot ~ 10^-5.5 to 10^-5.0 Msun/year at the time of the explosion, roughly consistent with the expected mass loss rates for a star of its temperature (T_* ~ 3600K) and luminosity. In the spirit of Galactic extinction laws, we supply simple interpolation formulas for circumstellar extinction by dusty graphitic and silicate shells as a function of wavelength (>0.3 micron) and total (absorption plus scattering) V-band optical depth (tau < 20). These do not include the contributions of dust emission, but provide a simple, physical alternative to incorrectly using interstellar extinction laws.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-08-20T20:02:06.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "case study",
      "progenitor",
      "ignore dust emission",
      "interstellar extinction laws",
      "optical/uv absorption"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/759/1/20",
      "journal": "The Astrophysical Journal",
      "year": 2012,
      "month": "Nov",
      "volume": 759,
      "number": 1,
      "pages": 20
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1128414,
      "adsabs": "2012ApJ...759...20K"
    }
  }
}