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Time-Series Analysis of Broadband Photometry of Neptune from K2

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posted on 2017-02-22, 16:05 authored by Jason F. Rowe, Patrick Gaulme, Jack J. Lissauer, Mark S. Marley, Amy A. Simon, Heidi B. Hammel, Víctor Silva Aguirre, Thomas Barclay, Othman Benomar, Patrick Boumier, Douglas A. Caldwell, Sarah L. Casewell, William J. Chaplin, Knicole D. Colón, Enrico Corsaro, G.R. Davies, Jonathan J. Fortney, Rafael A. Garcia, John E. Gizis, Michael R. Haas, Benoît Mosser, François-Xavier Schmider
We report here on our search for excess power in photometry of Neptune collected by the K2 mission that may be due to intrinsic global oscillations of the planet Neptune. To conduct this search, we developed new methods to correct for instrumental effects such as intrapixel variability and gain variations. We then extracted and analyzed the time-series photometry of Neptune from 49 days of nearly continuous broadband photometry of the planet. We find no evidence of global oscillations and place an upper limit of ~5 ppm at 1000 µHz for the detection of a coherent signal. With an observed cadence of 1-minute and point-to-point scatter less than 0.01%, the photometric signal is dominated by reflected light from the Sun, which is in turn modulated by atmospheric variability of Neptune at the 2% level. A change in flux is also observed due to the increasing distance between Neptune and the K2 spacecraft, and solar variability with convection-driven solar p modes present.


J.F.R. acknowledges NASA grant NNX14AB82G issued through the Kepler Participating Scientist Program. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant agreement No. DNRF106). The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (Grant agreement No. 267864). VSA. acknowledges support from VILLUM FONDEN (research grant 10118).



The Astronomical Journal, 2017, 153(4)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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American Astronomical Society, IOP Publishing





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Software: allmost (Rowe et al. 2006, 2008), montage2 (Stetson 1987), L-BFGS-B code (Zhu et al. 1997) 31 pages, 6 figure, accepted for publication in AJ The file associated with this record is under embargo until publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher.



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