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dc.contributor.authorBell, Taylor J.
dc.contributor.authorNikolov, Nikolay
dc.contributor.authorCowan, Nicolas B.
dc.contributor.authorBarstow, J.
dc.contributor.authorBarman, Travis S.
dc.contributor.authorCrossfield, Ian J. M.
dc.contributor.authorGibson, Neale P.
dc.contributor.authorEvans, Thomas M.
dc.contributor.authorSing, D. K.
dc.contributor.authorKnutson, Heather A.
dc.contributor.authorKataria, T.
dc.contributor.authorLothringer, Joshua D.
dc.contributor.authorBenneke, Björn
dc.contributor.authorSchwartz, Joel C.
dc.date.accessioned2017-10-09T15:43:13Z
dc.date.available2017-10-09T15:43:13Z
dc.date.issued2017-09-14
dc.identifier.citationThe Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubble 2017, 847 (1):L2 The Astrophysical Journalen
dc.identifier.issn2041-8213
dc.identifier.doi10.3847/2041-8213/aa876c
dc.identifier.urihttp://hdl.handle.net/10150/625800
dc.description.abstractWe present an optical eclipse observation of the hot Jupiter WASP-12b using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. These spectra allow us to place an upper limit of A(g) < 0.064 (97.5% confidence level) on the planet's white light geometric albedo across 290-570 nm. Using six wavelength bins across the same wavelength range also produces stringent limits on the geometric albedo for all bins. However, our uncertainties in eclipse depth are similar to 40% greater than the Poisson limit and may be limited by the intrinsic variability of the Sun-like host star-the solar luminosity is known to vary at the 10(-4) level on a timescale of minutes. We use our eclipse depth limits to test two previously suggested atmospheric models for this planet: Mie scattering from an aluminum-oxide haze or cloud-free Rayleigh scattering. Our stringent nondetection rules out both models and is consistent with thermal emission plus weak Rayleigh scattering from atomic hydrogen and helium. Our results are in stark contrast with those for the much cooler HD 189733b, the only other hot Jupiter with spectrally resolved reflected light observations; those data showed an increase in albedo with decreasing wavelength. The fact that the first two exoplanets with optical albedo spectra exhibit significant differences demonstrates the importance of spectrally resolved reflected light observations and highlights the great diversity among hot Jupiters.
dc.description.sponsorshipMcGill Space Institute; FRQNT through the Centre de recherche en astrophysique du Quebec; Royal Astronomical Society; Jet Propulsion Laboratory (JPL) - NASA; European Research Council under the European Union's Seventh Framework Programme/ERC [336792]; NASA [NAS 5-26555]en
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/2041-8205/847/i=1/a=L2?key=crossref.aee3b7ff54632992a852b2b81a8b9c41en
dc.rights© 2017. The American Astronomical Society. All rights reserved.en
dc.subjectplanets and satellites: atmospheresen
dc.subjectstars: individual (WASP-12)en
dc.subjecttechniques: photometricen
dc.titleThe Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubbleen
dc.typeArticleen
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
refterms.dateFOA2018-06-12T14:40:41Z
html.description.abstractWe present an optical eclipse observation of the hot Jupiter WASP-12b using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. These spectra allow us to place an upper limit of A(g) < 0.064 (97.5% confidence level) on the planet's white light geometric albedo across 290-570 nm. Using six wavelength bins across the same wavelength range also produces stringent limits on the geometric albedo for all bins. However, our uncertainties in eclipse depth are similar to 40% greater than the Poisson limit and may be limited by the intrinsic variability of the Sun-like host star-the solar luminosity is known to vary at the 10(-4) level on a timescale of minutes. We use our eclipse depth limits to test two previously suggested atmospheric models for this planet: Mie scattering from an aluminum-oxide haze or cloud-free Rayleigh scattering. Our stringent nondetection rules out both models and is consistent with thermal emission plus weak Rayleigh scattering from atomic hydrogen and helium. Our results are in stark contrast with those for the much cooler HD 189733b, the only other hot Jupiter with spectrally resolved reflected light observations; those data showed an increase in albedo with decreasing wavelength. The fact that the first two exoplanets with optical albedo spectra exhibit significant differences demonstrates the importance of spectrally resolved reflected light observations and highlights the great diversity among hot Jupiters.


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