{
  "id": "1611.03509",
  "version": "v1",
  "published": "2016-11-10T21:00:14.000Z",
  "updated": "2016-11-10T21:00:14.000Z",
  "title": "The H$α$ emission of nearby M dwarfs and its relation to stellar rotation",
  "authors": [
    "Elisabeth R. Newton",
    "Jonathan Irwin",
    "David Charbonneau",
    "Perry Berlind",
    "Michael L. Calkins",
    "Jessica Mink"
  ],
  "comment": "Accepted to ApJ. Machine readable tables available in ApJ or on request",
  "categories": [
    "astro-ph.SR",
    "astro-ph.EP"
  ],
  "abstract": "The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type stars, stellar rotation plays a pivotal role. We present 270 new optical spectra of low-mass stars in the Solar Neighborhood. Combining our observations with those from the literature, our sample comprises 2202 measurements or non-detections of H$\\alpha$ emission in nearby M dwarfs. This includes 466 with photometric rotation periods. Stars with masses between 0.1 and 0.6 solar masses are well-represented in our sample, with fast and slow rotators of all masses. We observe a threshold in the mass-period plane that separates active and inactive M dwarfs. The threshold coincides with the fast-period edge of the slowly rotating population, at approximately the rotation period at which an era of rapid rotational evolution appears to cease. The well- defined active/inactive boundary indicates that H$\\alpha$ activity is a useful diagnostic for stellar rotation period, e.g. for target selection for exoplanet surveys, and we present a mass-period relation for inactive M dwarfs. We also find a significant, moderate correlation between $L_{\\mathrm{H}\\alpha}/L_{\\mathrm{bol}}$ and variability amplitude: more active stars display higher levels of photometric variability. Consistent with previous work, our data show that rapid rotators maintain a saturated value of $L_{\\mathrm{H}\\alpha}/L_{\\mathrm{bol}}$. Our data also show a clear power-law decay in $L_{\\mathrm{H}\\alpha}/L_{\\mathrm{bol}}$ with Rossby number for slow rotators, with an index of $-1.7 \\pm 0.1$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-11-10T21:00:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar rotation",
      "stars display higher levels",
      "rotation period",
      "stars generate large-scale magnetic fields",
      "convective stars generate large-scale magnetic"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}