Program: GN-2018A-Q-312

Several ground- and space-based exoplanet surveys are being carried out to find transiting rocky planets. One way to highly optimize these searches is by targeting objects with a favorable geometry, i.e., those seen at their equator, since the orbit of a planet tends to lie perpendicular to the rotation axis of the host star. Here we propose to collect high-resolution near-infrared spectra of a sample of 23 M7-T6 dwarfs to measure their projected rotational velocities (vsini) by using GNIRS on the Gemini-N and the visitor instrument IGRINS on the Gemini-S telescopes. Our targets are expected to have a radius of 0.8-1 Rjup and there are published rotation periods for 12 of them. The combination of these parameters and the determination of the vsini's will allow us to derive the inclinations of the dwarfs' rotation axes, and to confirm most of them as excellent candidates to search for transiting Earth-sized planets. In addition, vsini's will provide insights in the angular momentum evolution at the substellar regime, and will allow us to investigate the likely relation between the spin orientation and the colors of ultra-cool dwarfs.