Precise Near-Infrared Radial Velocities

We present precise radial velocity time-series from a 2.3 micron near-infrared survey to detect exoplanets around ~30 red, low mass, and young stars. We use the CSHELL spectrograph (R~46,000) at the NASA InfraRed Telescope Facility, combined with an isotopic methane absorption gas cell for common optical path relative wavelength calibration. We have developed a sophisticated RV forward modeling code that accounts for fringing and other instrumental artifacts present in the spectra (see poster by Gao et al. at this meeting). We are able to reach long-term radial velocity dispersions of ~15-30 m/s on our survey targets. With a spectral grasp of only 5 nm, this performance is near the expected photon and detector noise limit. We highlight future applications of our instrumentation and RV forward modeling code to iSHELL at IRTF (R~75,000), and an upgraded NIRSPEC on the Keck II telescope (R~50,000). With the increased spectral grasp of both spectrometers, we should be able to obtain a precision of less than 5 m/s in the near-infrared.