{
  "id": "1506.01254",
  "version": "v1",
  "published": "2015-06-03T14:26:32.000Z",
  "updated": "2015-06-03T14:26:32.000Z",
  "title": "Spectroscopically resolving the Algol triple system",
  "authors": [
    "V. Kolbas",
    "K. Pavlovski",
    "J. Southworth",
    "C. -U. Lee",
    "D. -J. Lee",
    "J. W. Lee",
    "S. -L. Kim",
    "H. -I. Kim",
    "B. Smalley",
    "A. Tkachenko"
  ],
  "comment": "Accepted for publication in MNRAS",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Algol ($\\beta$ Persei) is the prototypical semi-detached eclipsing binary and a hierarchical triple system. From 2006 to 2010 we obtained 121 high-resolution and high-S/N \\'{e}chelle spectra of this object. Spectral disentangling yields the individual spectra of all three stars, and greatly improved elements both the inner and outer orbits. We find masses of $M_{\\rm A} = 3.39\\pm0.06$ M$_\\odot$, $M_{\\rm B} = 0.770\\pm0.009$ M$_\\odot$ and $M_{\\rm C} = 1.58\\pm0.09$ M$_\\odot$. The disentangled spectra also give the light ratios between the components in the $B$ and $V$ bands. Atmospheric parameters for the three stars are determined, including detailed elemental abundances for Algol A and Algol C. We find the following effective temperatures: $T_{\\rm A} = 12\\,550\\pm120$ K, $T_{\\rm B} = 4900\\pm300$ K and $T_{\\rm C} = 7550\\pm250$ K. The projected rotational velocities are $v_{\\rm A} \\sin i_{\\rm A} = 50.8\\pm0.8$ km/s, $v_{\\rm B} \\sin i_{\\rm B} = 62\\pm2$ km/s and $v_{\\rm C} \\sin i_{\\rm C} = 12.4\\pm0.6$ km/s. This is the first measurement of the rotational velocity for Algol B, and confirms that it is synchronous with the orbital motion. The abundance patterns of components A and C are identical to within the measurement errors, and are basically solar. They can be summarised as mean metal abundances: [M/H]$_{\\rm A} = -0.03\\pm0.08$ and [M/H]$_{\\rm C} = 0.04\\pm0.09$. A carbon deficiency is confirmed for Algol A, with tentative indications for a slight overabundance of nitrogen. The ratio of their abundances is (C/N)$_{\\rm A} = 2.0\\pm0.4$, half of the solar value of (C/N)$_{\\odot} = 4.0\\pm0.7$. The new results derived in this study, including detailed abundances and metallicities, will enable tight constraints on theoretical evolutionary models for this complex system.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-06-03T14:26:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "algol triple system",
      "spectroscopically resolving",
      "rotational velocity",
      "mean metal abundances",
      "solar value"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}