An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres

Persistent Link:
http://hdl.handle.net/10150/625491
Title:
An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres
Author:
Kempton, Eliza M.-R.; Bean, Jacob L. ( 0000-0003-4733-6532 ) ; Parmentier, Vivien
Affiliation:
Univ Arizona, Dept Planetary Sci; Univ Arizona, Lunar & Planetary Lab
Issue Date:
2017-08-18
Publisher:
IOP PUBLISHING LTD
Citation:
An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres 2017, 845 (2):L20 The Astrophysical Journal
Journal:
The Astrophysical Journal Letters
Rights:
© 2017. The American Astronomical Society. All rights reserved.
Collection Information:
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
Abstract:
The nature of aerosols in hot exoplanet atmospheres is one of the primary vexing questions facing the exoplanet field. The complex chemistry, multiple formation pathways, and lack of easily identifiable spectral features associated with aerosols make it especially challenging to constrain their key properties. We propose a transmission spectroscopy technique to identify the primary aerosol formation mechanism for the most highly irradiated hot Jupiters (HIHJs). The technique is based on the expectation that the two key types of aerosols-photochemically generated hazes and equilibrium condensate clouds-are expected to form and persist in different regions of a highly irradiated planet's atmosphere. Haze can only be produced on the permanent daysides of tidally locked hot Jupiters, and will be carried downwind by atmospheric dynamics to the evening terminator (seen as the trailing limb during transit). Clouds can only form in cooler regions on the nightside and morning terminator of HIHJs (seen as the leading limb during transit). Because opposite limbs are expected to be impacted by different types of aerosols, ingress and egress spectra, which primarily probe opposing sides of the planet, will reveal the dominant aerosol formation mechanism. We show that the benchmark HIHJ, WASP-121b, has a transmission spectrum consistent with partial aerosol coverage and that ingress-egress spectroscopy would constrain the location and formation mechanism of those aerosols. In general, using this diagnostic we find that observations with the James Webb Space Telescope and potentially with the Hubble Space Telescope should be able to distinguish between clouds and haze for currently known HIHJs.
ISSN:
2041-8213
DOI:
10.3847/2041-8213/aa84ac
Keywords:
methods: numerical; planets and satellites: atmospheres; planets and satellites: individual (WASP-121b); techniques: spectroscopic
Version:
Final published version
Sponsors:
Research Corporation for Science Advancement; Grinnell College's Harris Faculty Fellowship; NASA through STScI [GO-13665, GO-14792, 14793]; David and Lucile Packard Foundation; NASA Exoplanet Science Institute
Additional Links:
http://stacks.iop.org/2041-8205/845/i=2/a=L20?key=crossref.a9cb1bee6cf8b655c2a2043d7e98767a

Full metadata record

DC FieldValue Language
dc.contributor.authorKempton, Eliza M.-R.en
dc.contributor.authorBean, Jacob L.en
dc.contributor.authorParmentier, Vivienen
dc.date.accessioned2017-09-14T15:42:18Z-
dc.date.available2017-09-14T15:42:18Z-
dc.date.issued2017-08-18-
dc.identifier.citationAn Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres 2017, 845 (2):L20 The Astrophysical Journalen
dc.identifier.issn2041-8213-
dc.identifier.doi10.3847/2041-8213/aa84ac-
dc.identifier.urihttp://hdl.handle.net/10150/625491-
dc.description.abstractThe nature of aerosols in hot exoplanet atmospheres is one of the primary vexing questions facing the exoplanet field. The complex chemistry, multiple formation pathways, and lack of easily identifiable spectral features associated with aerosols make it especially challenging to constrain their key properties. We propose a transmission spectroscopy technique to identify the primary aerosol formation mechanism for the most highly irradiated hot Jupiters (HIHJs). The technique is based on the expectation that the two key types of aerosols-photochemically generated hazes and equilibrium condensate clouds-are expected to form and persist in different regions of a highly irradiated planet's atmosphere. Haze can only be produced on the permanent daysides of tidally locked hot Jupiters, and will be carried downwind by atmospheric dynamics to the evening terminator (seen as the trailing limb during transit). Clouds can only form in cooler regions on the nightside and morning terminator of HIHJs (seen as the leading limb during transit). Because opposite limbs are expected to be impacted by different types of aerosols, ingress and egress spectra, which primarily probe opposing sides of the planet, will reveal the dominant aerosol formation mechanism. We show that the benchmark HIHJ, WASP-121b, has a transmission spectrum consistent with partial aerosol coverage and that ingress-egress spectroscopy would constrain the location and formation mechanism of those aerosols. In general, using this diagnostic we find that observations with the James Webb Space Telescope and potentially with the Hubble Space Telescope should be able to distinguish between clouds and haze for currently known HIHJs.en
dc.description.sponsorshipResearch Corporation for Science Advancement; Grinnell College's Harris Faculty Fellowship; NASA through STScI [GO-13665, GO-14792, 14793]; David and Lucile Packard Foundation; NASA Exoplanet Science Instituteen
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/2041-8205/845/i=2/a=L20?key=crossref.a9cb1bee6cf8b655c2a2043d7e98767aen
dc.rights© 2017. The American Astronomical Society. All rights reserved.en
dc.subjectmethods: numericalen
dc.subjectplanets and satellites: atmospheresen
dc.subjectplanets and satellites: individual (WASP-121b)en
dc.subjecttechniques: spectroscopicen
dc.titleAn Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheresen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Dept Planetary Scien
dc.contributor.departmentUniv Arizona, Lunar & Planetary Laben
dc.identifier.journalThe Astrophysical Journal Lettersen
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
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