Improved precision on the radius of the nearby super-Earth 55 Cnc e
Name
Seager_Improved precision.pdf
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2.05 MB
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Author(s)
Gillon, M.
Demory, Brice-Olivier
Benneke, Bjoern
Valencia, Diana
Deming, Drake
Seager, Sara
Lovis, Christophe
Mayor, Michel
Pepe, F.
Queloz, D.
Date Issued
February 2012
Journal
Astronomy and Astrophysics
Publisher
EDP Sciences
Citation
Gillon, M. et al. “Improved Precision on the Radius of the Nearby super-Earth 55 Cnc e.” Astronomy & Astrophysics 539 (2012): A28.
Version
Author's final manuscript
Abstract
We report on new transit photometry for the super-Earth 55 Cnc e obtained with Warm Spitzer/IRAC at 4.5 μm. An individual analysis of these new data leads to a planet radius of [superscript 2.21]+0.15 [over] -0.16 R[subscript ⊕], which agrees well with the values previously derived from the MOST and Spitzer transit discovery data. A global analysis of both Spitzer transit time-series improves the precision on the radius of the planet at 4.5 μm to 2.20 ± 0.12 R[subscript ⊕]. We also performed an independent analysis of the MOST data, paying particular attention to the influence of the systematic effects of instrumental origin on the derived parameters and errors by including them in a global model instead of performing a preliminary detrending-filtering processing. We deduce an optical planet radius of 2.04 ± 0.15 R[subscript ⊕] from this reanalysis of MOST data, which is consistent with the previous MOST result and with our Spitzer infrared radius. Assuming the achromaticity of the transit depth, we performed a global analysis combining Spitzer and MOST data that results in a planet radius of 2.17 ± 0.10 R[subscript ⊕] (13 820 ± 620 km). These results point to 55 Cnc e having a gaseous envelope overlying a rocky nucleus, in agreement with previous works. A plausible composition for the envelope is water which would be in super-critical form given the equilibrium temperature of the planet.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1051/0004-6361/201118309
