I will present my analysis of a volume-complete sample of 363 mid-to-late M dwarfs within 15 pc of the Sun with masses between 0.1 and 0.3 MSun observed by TESS within sectors 1–42. The median stellar mass of the sample is 0.17 MSun. I perform a search for transiting planets with orbital periods below 7 days in TESS light curves and recover all known planets within the sample. Each of these planets is consistent with a terrestrial composition, with planet radii between 0.91 and 1.31 RSun. I then characterize the transit detection sensitivity for each individual star as a function of planet radius, insolation, and orbital period. This yields a cumulative occurrence rate of 0.61 [0.42, 0.85] terrestrial planets per star with radii above 0.5 RSun and orbital periods between 0.4 and 7 days. I find that for comparable insolations, planets larger than 1.5 RSun (sub-Neptunes) are significantly less abundant around mid-to-late M dwarfs compared to earlier-type stars, while the occurrence rate of terrestrial planets is comparable to that of more massive M dwarfs. I estimate that overall, terrestrials outnumber sub-Neptunes around mid-to-late M dwarfs by 14 to 1, in contrast to GK dwarfs, where they are roughly equinumerous. I place a 1-sigma upper limit of 0.07 planets larger than 1.5 RSun per star within the orbital period range of 0.5–7 days. I also present tentative evidence for a downturn in occurrence rates for planet radii below 0.9 RSun, suggesting that Earth-sized and larger terrestrials may be more common around mid-to-late M dwarfs.

Host: Suvrath Mahadevan

Seminar held in 538 Davey or please email CEHW-SEMINAR-QUESTIONS@lists.psu.edu to attend virtually.