SpeX survey on M dwarfs and giant planets

All metallicity measurements are homogeneously obtained through the same methodology based on the near-infrared spectra collected with a single instrument SpeX mounted on the NASA Infrared Telescope Facility.

We find that (1) giant planets favor metal-rich M dwarfs at a 4{sigma}-5{sigma} confidence level, depending on the band of spectra used to derive metallicity; (2) hot (a/R*<=20) and warm (a/R*>20) Jupiters do not show a significant difference in the metallicity distribution. Our results suggest that giant planets around M and FGK stars, which are already known to prefer metal-rich hosts, probably have a similar formation channel.