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We obtained spectra, in the wavelength range \lambda = 995 - 1769 nm, of allfour known planets orbiting the star HR 8799. Using the suite ofinstrumentation known as Project 1640 on the Palomar 5-m Hale Telescope, weacquired data at two epochs. This allowed for multiple imaging detections ofthe companions and multiple extractions of low-resolution (R ~ 35) spectra.Data reduction employed two different methods of speckle suppression andspectrum extraction, both yielding results that agree. The spectra do notdirectly correspond to those of any known objects, although similarities with Land T-dwarfs are present, as well as some characteristics similar to planetssuch as Saturn. We tentatively identify the presence of CH_4 along with NH_3and/or C_2H_2, and possibly CO_2 or HCN in varying amounts in each component ofthe system. Other studies suggested red colors for these faint companions, andour data confirm those observations. Cloudy models, based on previousphotometric observations, may provide the best explanation for the new datapresented here. Notable in our data is that these presumably co-eval objects ofsimilar luminosity have significantly different spectra; the diversity ofplanets may be greater than previously thought. The techniques and methodsemployed in this paper represent a new capability to observe and rapidlycharacterize exoplanetary systems in a routine manner over a broad range ofplanet masses and separations. These are the first simultaneous spectroscopicobservations of multiple planets in a planetary system other than our own.

Reconnaissance of the HR 8799 Exosolar System I: Near IR Spectroscopy