2mass 1315−2649: a High Proper Motion L Dwarf with Strong Hα Emission

In Hall (2002) I reported that 2MASSI J1315309−264951 is an L dwarf with strong Hα emission. Two spectroscopic epochs appeared to show that the Hα was variable, decreasing from 121 Å to 25 Å EW, which I interpreted as a flare during the first observation. Gizis (2002) independently discovered this object, and his intermediate spectroscopic epoch shows Hα with 97 Å EW. A new fourth epoch of spectroscopy again shows a very large Hα EW (124 Å), confirming this object to be a persistent, strong Hα emitter. Whether the Hα is steady (like 2MASS 1237+6526) or from continuous strong flaring (like PC0025+0447) remains unclear. Imaging confirms that 2MASS 1315−2649 has a high proper motion (0. 71 year), corresponding to a transverse velocity of ∼76 km s at its distance of ∼23 pc. Thus 2MASS 1315−2649 is consistent with being &2 Gyr old and therefore relatively massive. If that is so, the correlation of Hα activity with mass found by Gizis et al. (2000) would seem to support the continuous strong flaring scenario, though it does not rule out a brown dwarf binary accretion scenario. Subject headings: stars: activity, stars: low mass, brown dwarfs, stars: individual (2MASSI J1315309−264951, 2MASSI J1237392+652615, PC0025+0447)