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Title: New Formation Models for the Kepler-36 System

Journal Article · · The Astrophysical Journal (Online)
ORCiD logo [1]; ORCiD logo [2];  [3]; ORCiD logo [4]
  1. Univ. of California, Santa Cruz, CA (United States). UCO/Lick Observatory. Dept. of Astronomy and Astrophysics
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States). Division of Geological and Planetary Sciences
  3. NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States). Space Science and Astrobiology Division
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Formation of the planets in the Kepler-36 system is modeled here by detailed numerical simulations according to the core-nucleated accretion scenario. The standard model is updated to include the dissolution of accreting rocky planetesimals in the gaseous envelope of the planet, leading to substantial enrichment of the envelope mass in heavy elements and a non-uniform composition with depth. For Kepler-36 c, models involving in situ formation and models involving orbital migration are considered. The results are compared with standard formation models. The calculations include the formation (accretion) phase as well as the subsequent cooling phase, up to the age of Kepler-36 (7 Gyr). During the latter phase, mass loss induced by stellar XUV radiation is included. In all cases, the results fit the measured mass, 7.84 M , and radius, 3.68 R , of Kepler-36 c. Two parameters are varied to obtain these fits: the disk solid surface density at the formation location and the "efficiency" factor in the XUV mass-loss rate. The updated models are hotter and therefore less dense in the silicate portion of the planet and in the overlying layers of H/He, as compared with standard models. The lower densities mean that only about half as much H/He is needed to be accreted to fit the present-day mass and radius constraints. For Kepler-36 b, an updated in situ calculation shows that the entire H/He envelope is lost, early in the cooling phase, in agreement with observation.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States); Univ. of California, Santa Cruz, CA (United States); California Institute of Technology (CalTech), Pasadena, CA (United States)
Sponsoring Organization:
USDOE; National Aeronautics and Space Administration (NASA)
Grant/Contract Number:
89233218CNA000001; 15-EW15_2-0007; NNX14AG92G
OSTI ID:
1511233
Report Number(s):
LA-UR-18-23470
Journal Information:
The Astrophysical Journal (Online), Vol. 868, Issue 2; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 29 works
Citation information provided by
Web of Science

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Two Super-Earths in the 3:2 MMR around KOI-1599 journal March 2019
The Boundary between Gas-rich and Gas-poor Planets journal June 2019
Identifying Atmospheres on Rocky Exoplanets through Inferred High Albedo journal December 2019
TESS Hunt for Young and Maturing Exoplanets (THYME): A Planet in the 45 Myr Tucana–Horologium Association journal July 2019
Explaining the low luminosity of Uranus: a self-consistent thermal and structural evolution text January 2020
Jupiter’s heavy-element enrichment expected from formation models text January 2020
TESS Hunt for Young and Maturing Exoplanets (THYME): A planet in the 45 Myr Tucana-Horologium association text January 2019
Identifying Atmospheres on Rocky Exoplanets Through Inferred High Albedo text January 2019
Explaining the low luminosity of Uranus: A self-consistent thermal and structural evolution text January 2019
Jupiter's heavy-element enrichment expected from formation models text January 2019
Superabundance of Exoplanet Sub-Neptunes Explained by Fugacity Crisis text January 2019
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Setting the Stage: Planet formation and Volatile Delivery text January 2020
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