Detection of H alpha emission in a methane (T type) brown dwarf

Citation
Aj. Burgasser et al., Detection of H alpha emission in a methane (T type) brown dwarf, ASTRONOM J, 120(1), 2000, pp. 473-478
Citations number
47
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMICAL JOURNAL
ISSN journal
00046256 → ACNP
Volume
120
Issue
1
Year of publication
2000
Pages
473 - 478
Database
ISI
SICI code
0004-6256(200007)120:1<473:DOHAEI>2.0.ZU;2-1
Abstract
We report the detection of H alpha emission in the T dwarf (methane brown d warf) 2MASSW J1237392 + 652615 over three days using the Keek Low Resolutio n Imaging Spectrograph. The measured line flux, log (L-H alpha/L-bol) = -4. 3, is roughly consistent with early M dwarf activity levels and inconsisten t with decreasing activity trends in late M and L dwarfs. Similar emission is not seen in two other T dwarfs. We speculate on several mechanisms that may be responsible for emission, including a strong magnetic field, continu ous flaring, acoustic heat generation, and a close [a similar to (4-20)R-J] interacting binary, with the cooler component overflowing its Roche lobe. We suggest that the M9.5 Ve PC 0025 + 0447 could be a warm analog to 2MASS J1237+65 and may be powered by the latter mechanism.