Optical spectroscopy of a brown dwarf candidate

Abstract

We have used the Low-Resolution Imaging Spectrograph on the Keck II telescope to observe the brown dwarf candidate D04 (Hawkins et al, 1998). The spectrum matches that of a spectral-type M7 dwarf, implying a photospheric temperature of $\approx 2600$K. This is consistent with the available (R-I)${}_C$ and (I-K) colours. If the parallax measured by Hawkins et al is correct, then the implication is that D04 has a radius of $\sim 0.035R_{\odot }$, or one-third that of Jupiter. This contradicts the predictions made by current stellar models that electron degeneracy leads to nearly constant radii for stars and brown dwarfs at masses below 0.1 M${}_{\odot }$. We suggest that an equally valid interpretation of the data is that D04 is a VB8 analogue at a distance of $\approx 150$ parsecs.

to appear in MNRAS, pink pages; 6 pages with 1 jpg, 1 postscript figure

References in corpus (1)

• A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs

Cited by in corpus (1)

• Physical parameters of T dwarfs derived from high-resolution near-infrared spectra