Exoplanet Detection and Its Dependence on Stochastic Sampling of the Stellar Initial Mass Function

Abstract

Young moving groups (YMGs) are close (<100 pc), coherent collections of young (<100 Myr) stars that appear to have formed in the same star-forming molecular cloud. As such we would expect their individual initial mass functions (IMFs) to be similar to other star-forming regions, and by extension the Galactic field. Their close proximity to the Sun and their young ages means that YMGs are promising locations to search for young forming exoplanets. However, due to their low numbers of stars, stochastic sampling of the IMF means their stellar populations could vary significantly. We determine the range of planet-hosting stars (spectral types A, G, and M) possible from sampling the IMF multiple times, and find that some YMGs appear deficient in M-dwarfs. We then use these data to show that the expected probability of detecting terrestrial magma ocean planets is highly dependent on the exact numbers of stars produced through stochastic sampling of the IMF.

Timescales for Prebiotic Photochemistry Under Realistic Surface Ultraviolet Conditions

“…These constraints can also be transformed into conditions for further delineating the abiogenesis zone for the Sun, and for other stars, including for ultracool stars. This is especially relevant given our present knowledge about the UV environments of planetary systems around ultracool host stars such as TRAPPIST-1 (Ducrot et al, 2020) and systems discovered by TESS (Günther et al, 2020), and future discoveries around these systems, as well as around young exoplanet systems (Bottrill et al, 2020;Rimmer et al, 2020). If biosignatures are discovered on a statistically TIMESCALES FOR UV-DRIVEN PREBIOTIC PHOTOCHEMISTRY significant subset of these planets, the distribution of that subset may provide the only real way to test prebiotic chemical scenarios in the future.…”