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A map of the large day–night temperature gradient of a super-Earth exoplanet

Demory, Brice-Olivier and Gillon, Michaël and de Wit, Julien and Madhusudhan, Nikku and Bolmont, Emeline and Heng, Kevin and Kataria, Tiffany and Lewis, Nikole K. and Hu, Renyu and Krick, Jessica and Stamenković, Vlada and Benneke, Björn and Kane, Stephen and Queloz, Didier (2016) A map of the large day–night temperature gradient of a super-Earth exoplanet. Nature, 532 (7598). pp. 207-209. ISSN 0028-0836.

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[img] Image (JPEG) (Extended Data Figure 1: 55 Cancri e raw photometry) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 2: Continuation of Extended Data Fig. 1) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 3: Continuation of Extended Data Fig. 1) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 4: 55 Cancri e corrected photometry) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 5: Continuation of Extended Data Fig. 4) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 6: Continuation of Extended Data Fig. 4) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 7: Photometric r.m.s. versus bin size for all data sets) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 8: Polynomial-detrended phase-folded photometry) - Supplemental Material
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[img] Image (JPEG) (Extended Data Figure 9: Tidal heating constraints for 55 Cancri e) - Supplemental Material
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[img] Image (JPEG) (Extended Data Table 1: 55 Cancri e Spitzer data set) - Supplemental Material
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Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres, but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths—exoplanets with masses of one to ten times that of Earth—have so far revealed only featureless spectra. Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e (refs 4, 5) revealing highly asymmetric dayside thermal emission and a strong day–night temperature contrast. Dedicated space-based monitoring of the planet in the infrared revealed a modulation of the thermal flux as 55 Cancri e revolves around its star in a tidally locked configuration. These observations reveal a hot spot that is located 41 ± 12 degrees east of the substellar point (the point at which incident light from the star is perpendicular to the surface of the planet). From the orbital phase curve, we also constrain the nightside brightness temperature of the planet to 1,380 ± 400 kelvin and the temperature of the warmest hemisphere (centred on the hot spot) to be about 1,300 kelvin hotter (2,700 ± 270 kelvin) at a wavelength of 4.5 micrometres, which indicates inefficient heat redistribution from the dayside to the nightside. Our observations are consistent with either an optically thick atmosphere with heat recirculation confined to the planetary dayside, or a planet devoid of atmosphere with low-viscosity magma flows at the surface.

Item Type:Article
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URLURL TypeDescription ReadCube access Paper
Demory, Brice-Olivier0000-0002-9355-5165
Gillon, Michaël0000-0003-1462-7739
de Wit, Julien0000-0003-2415-2191
Madhusudhan, Nikku0000-0002-4869-000X
Bolmont, Emeline0000-0001-5657-4503
Heng, Kevin0000-0003-1907-5910
Kataria, Tiffany0000-0003-3759-9080
Lewis, Nikole K.0000-0002-8507-1304
Hu, Renyu0000-0003-2215-8485
Stamenković, Vlada0000-0003-2416-3683
Benneke, Björn0000-0001-5578-1498
Kane, Stephen0000-0002-7084-0529
Queloz, Didier0000-0002-3012-0316
Additional Information:© 2016 Macmillan Publishers Limited. Received 27 August 2015; Accepted 21 January 2016; Published online 30 March 2016. We thank D. Deming, D. Apai and A. Showman for discussions as well as the Spitzer Science Center staff for their assistance in the planning and executing of these observations. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. M.G. is a Research Associate at the Belgian Funds for Scientific Research (FRS-FNRS). V.S. was supported by the Simons Foundation (award number 338555, VS). Author Contributions: B.-O.D. initiated and led the Spitzer observing programme, conducted the data analysis and wrote the paper. M.G. performed an independent analysis of the dataset. E.B. carried out the simulations assessing the amplitude of tidal heating in the interior of 55 Cancri e. J.d.W. performed the longitudinal mapping of the planet. N.M. wrote the interpretation section with inputs from E.B., K.H., V.S., R.H., N.L. and T.K. J.K., B.B., S.K. and D.Q. contributed to the observing programme. All authors commented on the manuscript. The authors declare no competing financial interests.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
Simons Foundation338555
Issue or Number:7598
Record Number:CaltechAUTHORS:20160404-081727080
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Official Citation:A map of the large day–night temperature gradient of a super-Earth exoplanet Brice-Olivier Demory, Michael Gillon, Julien de Wit, Nikku Madhusudhan, Emeline Bolmont, Kevin Heng, Tiffany Kataria, Nikole Lewis, Renyu Hu, Jessica Krick, Vlada Stamenković, Björn Benneke, Stephen Kane & Didier Queloz Nature 532, 207–209 (14 April 2016) doi:10.1038/nature17169
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65875
Deposited By: Tony Diaz
Deposited On:04 Apr 2016 19:40
Last Modified:09 Mar 2020 13:18

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