NIRSPEC Radial Velocity Measurements of Late-M Dwarfs

TL;DR

This study demonstrates infrared radial velocity measurements of late-M dwarfs using NIRSPEC, achieving 150-300 m/s precision, and sets upper limits on planetary companions, aiding future exoplanet detection efforts around these stars.

Contribution

First infrared radial velocity survey of late-M dwarfs using telluric calibration, providing high-resolution spectra and rotational velocities for atmospheric modeling.

Findings

Achieved 150-300 m/s measurement precision over a year.

Placed upper limits of 5-10 MJ on potential planetary companions.

Provided high-resolution spectra for atmospheric studies.

Abstract

With an emphasis in detecting Earth-like planets set forth by the 2010 Decadal Survey and in searching for planets around M dwarfs set forth by the 2008 Exoplanet Task Force, radial velocity surveys with infrared echelle spectrometers will have a significant impact on future exoplanet studies. Here, we present the results of an infrared radial velocity survey of a sample of 14 late-M dwarfs with the NIRSPEC echelle spectrometer on the Keck II telescope. Using telluric lines for wavelength calibration, we are able to achieve measurement precisions of 150-300 m/s over a year-long timeframe. While we require more RV epochs to determine whether most of our stars have planetary-mass companions, we have placed upper limits of 5-10 MJ on the masses of planets around a sub-set of our sample. We have also determined the rotational velocities for all the stars in the sample and offer our multi-order, high-resolution spectra over 2.0 to 2.4 micron to the modeling community to better understand the atmospheres of late-M dwarfs.