{
  "id": "1905.03784",
  "version": "v1",
  "published": "2019-05-09T18:00:00.000Z",
  "updated": "2019-05-09T18:00:00.000Z",
  "title": "Relation between gravitational mass and baryonic mass for non-rotating and rapidly rotating neutron stars",
  "authors": [
    "He Gao",
    "Shun-Ke Ai",
    "Zhou-Jian Cao",
    "Bing Zhang",
    "Zhen-Yu Zhu",
    "Ang Li",
    "Nai-Bo Zhang",
    "Andreas Bauswein"
  ],
  "comment": "7 pages, 3 figures",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "With a selected sample of neutron star (NS) equation-of-states (EOSs) that are consistent with the current observations and have a range of maximum masses, we investigate the relations between NS gravitational mass $M_g$ and baryonic mass $M_b$, and the relations between the maximum NS mass supported through uniform rotation ($M_{\\rm max}$) and that of nonrotating NSs ($M_{\\rm TOV}$). We find that if one intends to apply an EOS-independent quadratic, universal transformation formula ($M_b=M_g+A\\times M_{g}^2$) to all EOSs, the best fit $A$ value is 0.080 for non-rotating NSs only and 0.073 when different spin periods are considered. The residual error of the transformation is as large as $\\sim0.1M_{\\odot}$. For different EOSs, we find that the parameter $A$ for non-rotating NSs is proportional to $R_{1.4}^{-1}$ (where $R_{1.4}$ is NS radius for 1.4$M_\\odot$ in unit of km). For a particular EOS, if one adopts the best-fit parameters for different spin periods, the residual error of the transformation is smaller, which is of the order of 0.01$M_\\odot$ for the quadratic form and less than 0.01$M_\\odot$ for the cubic form ($M_b=M_g+A_1\\times M_{g}^2+A_2\\times M_{g}^3$). We also find a very tight and general correlation between the normalized mass gain due to spin $\\Delta m\\equiv(M_{\\rm max}-M_{\\rm TOV})/M_{\\rm TOV}$ and the spin period normalized to the Keplerian period ${\\cal P}$, i.e. ${\\rm log_{10}}\\Delta m = (-2.74\\pm0.05){\\rm log_{10}}{\\cal P}+{\\rm log_{10}}(0.20\\pm 0.01)$, which is independent of EOS models. Applications of our results to GW170817 is discussed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-05-09T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "rapidly rotating neutron stars",
      "baryonic mass",
      "spin period",
      "residual error",
      "non-rotating"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}