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Masses and Properties of Extrasolar Planets.

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Title:Masses and Properties of Extrasolar Planets.
Authors:Sinukoff, Evan J.
Contributors:Astronomy (department)
Keywords:astronomy
exoplanets
Date Issued:Aug 2018
Publisher:University of Hawaiʻi at Mānoa
Abstract:NASA's Kepler Mission revealed that the majority of planets orbiting close to Sun-like stars are
between the size of Earth and Neptune. Yet these \super-Earths" and \sub-Neptunes" are absent
from our Solar System. The distributions of planet properties measured by Kepler | radii and
orbital periods | have been precisely measured, but we do not yet have a good understanding
of their masses and bulk compositions, which can ultimately be linked to their origins. Follow-up
measurements of the masses of a few dozen Kepler planets demonstrated that planets smaller than 1.5 Earth-radii are predominantly rocky, while larger planets typically have gaseous envelopes.
Measurements of mass and radius do not provide a one-to-one relationship, indicating that compositions
might depend on environmental parameters like temperature, and properties of the host
star. Building on this, we leverage NASA's K2 mission to identify and measure the masses of
dozens more small planets orbiting bright stars. After nearly doubling the number of small planets
with measured densities, and precisely characterizing each host star, we re-examined the distribution of planet bulk compositions, the transition from rocky to gas-dominated planets, and their dependencies on temperature and host star properties. Planet core mass is correlated with host
star metallicity, suggesting that the availability of solids aects planet composition. There are two
distinct planet populations | \super-Earths" consisting of 1{2 R cores with little to no gas, and
larger \sub-Neptunes" with H/He envelopes comprising & 1% of their total mass. The gap between
these populations appears devoid of sub-Neptunes with the most tenuous atmospheres (<1%
H/He), indicating that such planets experience complete photoevaporation.
Description:Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018.
URI:http://hdl.handle.net/10125/62172
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Astronomy


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