{
  "id": "astro-ph/9410074",
  "version": "v1",
  "published": "1994-10-24T10:29:13.000Z",
  "updated": "1994-10-24T10:29:13.000Z",
  "title": "Interstellar Titanium in the Galactic Halo",
  "authors": [
    "Keith Lipman",
    "Max Pettini"
  ],
  "comment": "Accepted for publication in ApJ, due to appear 1 April 1995. 23 pages including 5 figures; uuencoded compressed postscript; RG0-212",
  "doi": "10.1086/175466",
  "categories": [
    "astro-ph"
  ],
  "abstract": "We present observations of Ti~II~$\\lambda 3384$ absorption towards 15 distant stars in the Galactic halo and the Magellanic Clouds. These new data extend existing surveys of the distribution of Ti$^+$ to larger distances from the plane of the Galaxy than sampled previously, allowing the scale height of titanium to be determined for the first time. We find $h_{Ti^+} = 1.5 \\pm 0.2$~kpc, a value which although greater than those of other tracers of neutral gas, is not as large as had been suspected. We interpret the extended distribution of Ti$^+$ as an indication that its severe depletion in interstellar clouds in the disk is reduced at the lower densities prevailing in the halo. The data are consistent with a simple power-law dependence of the Ti abundance on the ambient density, with exponent $k \\simeq -1$. If the model is correct, it implies that refractory elements like Ti are fully returned to the gas phase at distances beyond $\\sim 1$ kpc from the plane of the Galaxy.",
  "revisions": [
    {
      "version": "v1",
      "updated": "1994-10-24T10:29:13.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galactic halo",
      "interstellar titanium",
      "data extend existing surveys",
      "simple power-law dependence",
      "gas phase"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 23,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 390679
    }
  }
}