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Title: Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy

Abstract

MassSpec , a method for determining the mass of a transiting exoplanet from its transmission spectrum alone, was proposed by de Wit and Seager. The premise of this method relies on the planet’s surface gravity being extracted from the transmission spectrum via its effect on the atmospheric scale height, which in turn determines the strength of absorption features. Here, we further explore the applicability of MassSpec to low-mass exoplanets—specifically those in the super-Earth size range for which radial velocity determinations of the planetary mass can be extremely challenging and resource intensive. Determining the masses of these planets is of the utmost importance because their nature is otherwise highly unconstrained. Without knowledge of the mass, these planets could be rocky, icy, or gas-dominated. To investigate the effects of planetary mass on transmission spectra, we present simulated observations of super-Earths with atmospheres made up of mixtures of H{sub 2}O and H{sub 2}, both with and without clouds. We model their transmission spectra and run simulations of each planet as it would be observed with James Webb Space Telescope using the NIRISS, NIRSpec, and MIRI instruments. We find that significant degeneracies exist between transmission spectra of planets with different masses and compositions, makingmore » it impossible to unambiguously determine the planet’s mass in many cases.« less

Authors:
 [1];  [2];  [3]
  1. Department of Astronomy and Astrophysics, Pennsylvania State University, State College, PA 16802 (United States)
  2. Department of Physics, Grinnell College, 1116 8th Avenue, Grinnell, IA 50112 (United States)
  3. Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)
Publication Date:
OSTI Identifier:
22654548
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 836; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; GRAVITATION; HYDROGEN; MASS; PLANETS; RADIAL VELOCITY; RESOURCES; SATELLITE ATMOSPHERES; SATELLITES; SCALE HEIGHT; SIMULATION; SPACE; SPECTRA; TELESCOPES; TRANSMISSION

Citation Formats

Batalha, Natasha E., Kempton, Eliza M.-R., and Mbarek, Rostom, E-mail: neb149@psu.edu. Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA5C7D.
Batalha, Natasha E., Kempton, Eliza M.-R., & Mbarek, Rostom, E-mail: neb149@psu.edu. Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy. United States. doi:10.3847/2041-8213/AA5C7D.
Batalha, Natasha E., Kempton, Eliza M.-R., and Mbarek, Rostom, E-mail: neb149@psu.edu. Fri . "Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy". United States. doi:10.3847/2041-8213/AA5C7D.
@article{osti_22654548,
title = {Challenges to Constraining Exoplanet Masses via Transmission Spectroscopy},
author = {Batalha, Natasha E. and Kempton, Eliza M.-R. and Mbarek, Rostom, E-mail: neb149@psu.edu},
abstractNote = {MassSpec , a method for determining the mass of a transiting exoplanet from its transmission spectrum alone, was proposed by de Wit and Seager. The premise of this method relies on the planet’s surface gravity being extracted from the transmission spectrum via its effect on the atmospheric scale height, which in turn determines the strength of absorption features. Here, we further explore the applicability of MassSpec to low-mass exoplanets—specifically those in the super-Earth size range for which radial velocity determinations of the planetary mass can be extremely challenging and resource intensive. Determining the masses of these planets is of the utmost importance because their nature is otherwise highly unconstrained. Without knowledge of the mass, these planets could be rocky, icy, or gas-dominated. To investigate the effects of planetary mass on transmission spectra, we present simulated observations of super-Earths with atmospheres made up of mixtures of H{sub 2}O and H{sub 2}, both with and without clouds. We model their transmission spectra and run simulations of each planet as it would be observed with James Webb Space Telescope using the NIRISS, NIRSpec, and MIRI instruments. We find that significant degeneracies exist between transmission spectra of planets with different masses and compositions, making it impossible to unambiguously determine the planet’s mass in many cases.},
doi = {10.3847/2041-8213/AA5C7D},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 836,
place = {United States},
year = {Fri Feb 10 00:00:00 EST 2017},
month = {Fri Feb 10 00:00:00 EST 2017}
}