Friends not Foes: Strong Correlation between Inner Super-Earths and Outer Gas Giants
Abstract
The connection between outer gas giants and inner super-Earths reflects their formation and evolutionary histories. Past work exploring this link has suggested a tentative positive correlation between these two populations, but these studies have been limited by small sample sizes and in some cases sample biases. Here we take a new look at this connection with a sample of 184 super-Earth systems with publicly available radial velocity data and resolved outer gas giants. We calculate the frequency of outer gas giants (GG) in super-Earth (SE) systems, dividing our sample into metal-rich ([Fe/H] 0) and metal-poor ([Fe/H]0) hosts. We find P(GGSE, [Fe/H]0) = 28.0 and P(GGSE, [Fe/H]0) = 4.5. Comparing these conditional occurrence rates to field giant occurrence rates from Rosenthal et al 2021, we show that there is a distinct positive correlation between inner super-Earths and outer gas giants for metal-rich host stars at the 2.7 level, but this correlation disappears for metal-poor systems. We further find that, around metal-rich stars, the GG/SE correlation enhances slightly for systems with giants that are more distant (beyond 3 AU), more eccentric (), and/or in multi-gas giant systems. Such trends disappear around metal-poor stars with the exception of systems of multiple giants in which we observe a tentative anti-correlation. Our findings highlight the critical role metallicity (disk solid budget) plays in shaping the overall planetary architecture.
Keywords
Cite
@article{arxiv.2403.08873,
title = {Friends not Foes: Strong Correlation between Inner Super-Earths and Outer Gas Giants},
author = {Marta L. Bryan and Eve J. Lee},
journal= {arXiv preprint arXiv:2403.08873},
year = {2024}
}
Comments
accepted to ApJL