TESS planets in known radial velocity cold Jupiter systems: Hot super Earth occurrence is enhanced by cold Jupiters

TL;DR

The paper investigates whether inner hot super‑Earths are more likely to occur in systems that host outer cold Jupiters, addressing uncertainties in previous observational studies. It combines a well‑defined RV CJ sample with a uniform TESS transit search, validating two SE candidates around HD 50554 and modeling transit geometry and detection completeness to estimate $P({\rm SE}|{\rm CJ})$. The authors identify five transiting hot SEs across four CJ hosts, including a new candidate around HD 50554, and find that CJ systems exhibit an SE occurrence enhanced by $8.1^{+4.3}_{-3.2}$ relative to field stars, corresponding to about $87\%$ of CJ systems hosting at least one hot SE. These results provide strong evidence for a positive SE–CJ correlation and have significant implications for planet formation and dynamical evolution theories, including considerations of metallicity dependence and subpopulation trends.

Abstract

The correlation between inner super-Earths (SEs) and outer cold Jupiters (CJs) provides an important constraint on the formation and dynamical evolution of planetary systems. Previous studies have suggested a positive connection between these two populations, particularly around metal-rich stars, and proposed that nearly all CJ-hosting stars may also harbor inner SEs. In this work, we use TESS transits to investigate the occurrence of hot SEs in systems with known CJs detected by radial velocity (RV). Out of a statistical sample of 132 CJ systems, we identify five transiting hot super-Earths ($1$-$4R_\oplus$, $P<10\mathrm{d}$) around four stars, including one new candidate (TOI-6965.01) around HD 50554. To enable statistical analysis, we first validate the two candidates around HD 50554 using TESS photometry, archival RV measurements, and Gaia astrometry. After accounting for detection sensitivity and geometric transit probability, we find that the presence of CJs enhances the occurrence rate of hot super-Earths by a factor of $8.1^{+4.3}_{-3.2}$ relative to field stars, with the case of no enhancement ruled out at the 99.9% confidence level. Taking into account the average multiplicity of hot SEs, we find that about 87% of CJ systems host at least one hot SE. Our results provide strong supporting evidence for a positive SE-CJ correlation. We also briefly explore the correlation around metal-poor hosts and for specific sub-populations (e.g., warm super-Earths or cold super-Jupiters).

Figures (2)

• Figure 1: Planet mass (or minimum mass) as a function of orbital period for planetary systems hosting cold Jupiters. Gray points represent the full population of confirmed exoplanets from the NASA Exoplanet Archive. The dashed box outlines the parameter space adopted for CJs and HSEs in this work. Colored stars denote systems in our sample that host both a CJ and at least one inner SE detected by TESS: HD 219134, $\pi$ Mensae, HD 50554, and HD 86226. Cyan circles indicate CJs in our RV-selected sample without detected transiting inner SEs. Other HSEs detected via RV, along with planets in their systems, are marked by pink circles. Planets belonging to the same system are connected by dashed lines.
• Figure 2: The distribution of the cold Jupiter host stars in our sample. Left: The histogram of stellar mass. Right: The histogram of TESS magnitude.