Exoplanet detection and its dependence on stochastic sampling of the stellar Initial Mass Function

TL;DR

This paper investigates how stochastic sampling of the stellar initial mass function in young moving groups affects the expected number of planet-hosting stars and the likelihood of detecting young exoplanets.

Contribution

It quantifies the variability in stellar populations due to stochastic IMF sampling and its impact on exoplanet detection prospects in young moving groups.

Findings

Some YMGs are deficient in M-dwarfs due to stochastic sampling.

The probability of detecting magma ocean planets varies significantly with stellar population sampling.

Stochastic effects can influence target selection for exoplanet surveys.

Abstract

Young Moving Groups (YMGs) are close (<100pc), coherent collections of young (<100Myr) 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.