Abstract
We report on the analysis of high-resolution infrared spectra of the newly discovered brown dwarf epsilon Ind Ba. This is the closest known brown dwarf to the solar system, with a distance of 3.626 pc. Spectra covering the ranges of lambdalambda2.308-2.317 mum and lambdalambda1.553-1.559 mum were observed at a resolution of lambda/Deltalambda = R = 50,000. The physical parameters of effective temperature and surface gravity are derived for e Ind Ba by comparison with model spectra calculated from atmospheres computed using unified cloudy models. The results are T-eff = 1500 +/- 100 K, log g = 5.2 +/- 0.3 (in units of cm s(-2)), placing it in the critical boundary between the late L and early T dwarfs. The high spectral resolution also allows us to measure an accurate projected rotational velocity, with v sin i = 28 +/- 3 km s(-1). Combined with a published luminosity for epsilon Ind Ba [with log (L/L.) = -4.71], the derived parameters result in a "spectroscopic" mass estimate of similar to30M(J), a radius of similar to0.062 R., and a maximum rotational period of similar to3.0 hr. A compilation and comparison of effective temperatures derived from spectroscopy using model atmospheres versus those derived from luminosities and theoretical M-bol-radius relations reveal a systematic disagreement in the Teff scale. The source of this disagreement is unknown.
| Original language | English |
|---|---|
| Pages (from-to) | L107-L110 |
| Number of pages | 4 |
| Journal | The Astrophysical Journal |
| Volume | 599 |
| Issue number | 2 |
| Publication status | Published - 20 Dec 2003 |
Keywords
- infrared : stars
- stars : fundamental parameters
- stars : individual (epsilon Indi B)
- stars : low-mass, brown dwarfs
- T-DWARF
- MICRONS