{
  "id": "1212.3962",
  "version": "v1",
  "published": "2012-12-17T11:40:02.000Z",
  "updated": "2012-12-17T11:40:02.000Z",
  "title": "The 12C + 12C reaction and the impact on nucleosynthesis in massive stars",
  "authors": [
    "M. Pignatari",
    "R. Hirschi",
    "M. Wiescher",
    "R. Gallino",
    "M. Bennett",
    "M. Beard",
    "C. Fryer",
    "F. Herwig",
    "G. Rockefeller",
    "F. X. Timmes"
  ],
  "journal": "The Astrophysical Journal 2013, 762, 31",
  "doi": "10.1088/0004-637X/762/1/31",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Despite much effort in the past decades, the C-burning reaction rate is uncertain by several orders of magnitude, and the relative strength between the different channels 12C(12C,alpha)20Ne, 12C(12C,p)23Na and 12C(12C,n)23Mg is poorly determined. Additionally, in C-burning conditions a high 12C+12C rate may lead to lower central C-burning temperatures and to 13C(alpha,n)16O emerging as a more dominant neutron source than 22Ne(alpha,n)25Mg, increasing significantly the s-process production. This is due to the rapid decrease of the 13N(gamma,p)12C with decreasing temperature, causing the 13C production via 13N(beta+)13C. Presented here is the impact of the 12C+12C reaction uncertainties on the s-process and on explosive p-process nucleosynthesis in massive stars, including also fast rotating massive stars at low metallicity. Using various 12C+12C rates, in particular an upper and lower rate limit of ~ 50000 higher and ~ 20 lower than the standard rate at 5*10^8 K, five 25 Msun stellar models are calculated. The enhanced s-process signature due to 13C(alpha,n)16O activation is considered, taking into account the impact of the uncertainty of all three C-burning reaction branches. Consequently, we show that the p-process abundances have an average production factor increased up to about a factor of 8 compared to the standard case, efficiently producing the elusive Mo and Ru proton-rich isotopes. We also show that an s-process being driven by 13C(alpha,n)16O is a secondary process, even though the abundance of 13C does not depend on the initial metal content. Finally, implications for the Sr-peak elements inventory in the Solar System and at low metallicity are discussed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-12-17T11:40:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "massive stars",
      "12c reaction",
      "nucleosynthesis",
      "low metallicity",
      "c-burning reaction"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "The Astrophysical Journal",
      "year": 2013,
      "month": "Jan",
      "volume": 762,
      "number": 1,
      "pages": 31
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1207536,
      "adsabs": "2013ApJ...762...31P"
    }
  }
}