Precise stellar radial velocities of an m dwarf with a Michelson interferometer and a medium-resolution near-infrared spectrograph

Precise near-infrared radial velocimetry enables efficient detection and transit verification of lowmass extrasolar planets orbiting M-dwarf hosts, which are faint for visible-wavelength radial velocity surveys. The TripleSpec Exoplanet Discovery Instrument (TEDI) is the combination of a variable-delay Michelson interferometer and a medium-resolution (R 1/4 2700) near-infrared spectrograph on the Palomar 200 inch (5 m) Hale Telescope.We used TEDI to monitor GJ 699, a nearby mid-M dwarf, over 11 nights spread across 3 months. Analysis of 106 independent observations reveals a root-mean-squared precision of less than 37 ms^-1 for 5 minutes of integration time. This performance is within a factor of 2 of our expected photon-limited precision. We further decompose the residuals into a 33 ms^-1 white noise component and a 15 ms^-1 systematic noise component, which we identify as being likely due to contamination by telluric absorption lines. With further development this technique holds promise for broad implementation on medium-resolution near-infrared spectrographs to search for low-mass exoplanets orbiting M dwarfs and to verify low-mass transit candidates.