Session 19 - Solar & Planetary Systems.
Display session, Monday, January 13
Metropolitan Ballroom,

## [19.07] Measurements of the Brown Dwarf Gliese 229B

B. R. Oppenheimer, S. R. Kulkarni, K. Matthews, T. Nakajima (California Institute of Technology), D. A. Golimowski (The Johns Hopkins University)

We present a thorough observational study of the brown dwarf Gliese 229B. Our observations span the wavelength range from 0.675 \mu to 10.5 \mu, and include high resolution spectroscopy from 0.850 \mu to 2.5 \mu. The energy distribution of the emission is largely concentrated near 1 \mu, and bears no resemblance to a black-body spectrum. The detected luminosity of Gliese 229B is (4.9 \pm 0.6) \times 10^-6 L_ødot, which according to models is 80% of the total luminosity, L_bol = 6.4 \times 10^-6 L_ødot, corresponding to T_eff = 900K. The spectra, similar only to spectra of Jupiter and Titan, reveal absorption due to many sources of opacity, including, most importantly, CH_4 and H_2O. Detailed study of the absorption due to these molecules is possible, much in the manner of studies of the Jovian planets. HST observations indicate that the parallax of Gliese 229B is identical to that of Gliese 229A, confirming our previous claim of companionship between these two objects based on common proper motion. Gliese 229B lies 39 AU from A (an M1 V star). The mass of Gliese 229B will be determined in the coming year through detailed spectroscopy in the 3, 5 and 10 \mu regions, where absorption due to NH_3, PH_3, CO, AsH_3 and GeH_4 may be apparent. The discovery and detailed studies of Gliese 229B prove imaging and spectroscopic techniques that will be needed in the search for, and study of, earth-like planets around nearby stars.

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The author(s) of this abstract have provided an email address for comments about the abstract: bro@astro.caltech.edu