Kepler-167e as a Probe of the Formation Histories of Cold Giants with Inner Super-Earths
Abstract
The observed correlation between outer giant planets and inner super-Earths is emerging as an important constraint on planet formation theories. In this study, we focus on Kepler-167, which is currently the only system known to contain both inner transiting super-Earths and a confirmed outer transiting gas giant companion beyond 1 au. Using long-term radial velocity monitoring, we measure the mass of the gas giant Kepler-167e (P = 1071 days) to be ?{1.01}_{-0.15}^{+0.16}$ M J, thus confirming it as a Jupiter analog. We refit the Kepler photometry to obtain updated radii for all four planets. Using a planetary structure model, we estimate that Kepler-167e contains 66 ± 19 M ⊕ of solids and is significantly enriched in metals relative to its solar-metallicity host star. We use these new constraints to explore the broader question of how systems like Kepler-167 form in the pebble accretion framework for giant planet core formation. We utilize simple disk evolution models to demonstrate that more massive and metal-rich disks, which are the most favorable sites for giant planet formation, can also deliver enough solids to the inner disk to form systems of super-Earths. We use these same models to constrain the nature of Kepler-167's protoplanetary disk and find that it likely contained ≳300 M ⊕ of dust and was ≳40 au in size. These values overlap with the upper end of the observed dust mass and size distributions of Class 0 and I disks and are also consistent with the observed occurrence rate of Jupiter analogs around Sun-like stars.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2022
- DOI:
- 10.3847/1538-4357/ac3ed6
- arXiv:
- arXiv:2112.00747
- Bibcode:
- 2022ApJ...926...62C
- Keywords:
-
- 1241;
- 1655;
- 509;
- 1332;
- 1300;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- accepted for publication in ApJ, 19 pages, 10 figures. Table 1 will be provided in MRT format upon publication