skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

This content will become publicly available on October 29, 2019

Title: Growth model interpretation of planet size distribution

Abstract

The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be determined by ground-based spectroscopic observations, these observations allow calculation of their average densities placing constraints on the bulk compositions and internal structures. However, an important question about the composition of planets ranging from 2 to 4 Earth radii (R ) still remains. They may either have a rocky core enveloped in a H 2 –He gaseous envelope (gas dwarfs) or contain a significant amount of multicomponent, H 2 O-dominated ices/fluids (water worlds). Planets in the mass range of 10–15 M , if half-ice and half-rock by mass, have radii of 2.5 R , which exactly match the second peak of the exoplanet radius bimodal distribution. Any planet in the 2- to 4-R range requires a gas envelope of at most a few mass percentage points, regardless of the core composition. To resolve the ambiguity of internal compositions, we use a growth model and conduct Monte Carlomore » simulations to demonstrate that many intermediate-size planets are “water worlds.”« less

Authors:
ORCiD logo; ; ; ; ; ; ORCiD logo; ; ; ; ; ; ; ORCiD logo; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1509918
Grant/Contract Number:  
NA0001804; NA0002937; NA-0003525
Resource Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

Zeng, Li, Jacobsen, Stein B., Sasselov, Dimitar D., Petaev, Michail I., Vanderburg, Andrew, Lopez-Morales, Mercedes, Perez-Mercader, Juan, Mattsson, Thomas R., Li, Gongjie, Heising, Matthew Z., Bonomo, Aldo S., Damasso, Mario, Berger, Travis A., Cao, Hao, Levi, Amit, and Wordsworth, Robin D. Growth model interpretation of planet size distribution. United States: N. p., 2019. Web. doi:10.1073/pnas.1812905116.
Zeng, Li, Jacobsen, Stein B., Sasselov, Dimitar D., Petaev, Michail I., Vanderburg, Andrew, Lopez-Morales, Mercedes, Perez-Mercader, Juan, Mattsson, Thomas R., Li, Gongjie, Heising, Matthew Z., Bonomo, Aldo S., Damasso, Mario, Berger, Travis A., Cao, Hao, Levi, Amit, & Wordsworth, Robin D. Growth model interpretation of planet size distribution. United States. doi:10.1073/pnas.1812905116.
Zeng, Li, Jacobsen, Stein B., Sasselov, Dimitar D., Petaev, Michail I., Vanderburg, Andrew, Lopez-Morales, Mercedes, Perez-Mercader, Juan, Mattsson, Thomas R., Li, Gongjie, Heising, Matthew Z., Bonomo, Aldo S., Damasso, Mario, Berger, Travis A., Cao, Hao, Levi, Amit, and Wordsworth, Robin D. Mon . "Growth model interpretation of planet size distribution". United States. doi:10.1073/pnas.1812905116.
@article{osti_1509918,
title = {Growth model interpretation of planet size distribution},
author = {Zeng, Li and Jacobsen, Stein B. and Sasselov, Dimitar D. and Petaev, Michail I. and Vanderburg, Andrew and Lopez-Morales, Mercedes and Perez-Mercader, Juan and Mattsson, Thomas R. and Li, Gongjie and Heising, Matthew Z. and Bonomo, Aldo S. and Damasso, Mario and Berger, Travis A. and Cao, Hao and Levi, Amit and Wordsworth, Robin D.},
abstractNote = {The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be determined by ground-based spectroscopic observations, these observations allow calculation of their average densities placing constraints on the bulk compositions and internal structures. However, an important question about the composition of planets ranging from 2 to 4 Earth radii (R ⊕ ) still remains. They may either have a rocky core enveloped in a H 2 –He gaseous envelope (gas dwarfs) or contain a significant amount of multicomponent, H 2 O-dominated ices/fluids (water worlds). Planets in the mass range of 10–15 M ⊕ , if half-ice and half-rock by mass, have radii of 2.5 R ⊕ , which exactly match the second peak of the exoplanet radius bimodal distribution. Any planet in the 2- to 4-R ⊕ range requires a gas envelope of at most a few mass percentage points, regardless of the core composition. To resolve the ambiguity of internal compositions, we use a growth model and conduct Monte Carlo simulations to demonstrate that many intermediate-size planets are “water worlds.”},
doi = {10.1073/pnas.1812905116},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {4}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on October 29, 2019
Publisher's Version of Record

Save / Share: