Jupiter's Phase Variations from Cassini: a testbed for future direct-imaging missions

Status Report From: e-Print archive
Posted: Wednesday, October 26, 2016

L. C. Mayorga, J. Jackiewicz, K. Rages, R. A. West, B. Knowles, N. Lewis, M. S. Marley
(Submitted on 24 Oct 2016)

We present phase curves of Jupiter from 0-140 degrees as measured in multiple optical bandpasses by Cassini/ISS during the Millennium flyby of Jupiter in late 2000 to early 2001. Phase curves are of interest for studying the energy balance of Jupiter and understanding the scattering behavior of Jupiter as an exoplanet analog. We find that Jupiter is significantly darker at partial phases than an idealized Lambertian planet by roughly 25% and is not well fit by Jupiter-like exoplanet atmospheric models across all wavelengths. We provide analytic fits to Jupiter's phase function in several Cassini/ISS imaging filter bandpasses. In addition, these observations show that Jupiter's color is more variable with phase angle than predicted by models. Therefore, the color of even a near Jupiter-twin planet observed at a partial phase cannot be assumed to be comparable to that of Jupiter at full phase. We discuss how WFIRST and other future direct-imaging missions can enhance the study of cool giants.

Comments: 29 pages, 9 figures, accepted to AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1610.07679 [astro-ph.EP] (or arXiv:1610.07679v1 [astro-ph.EP] for this version)
Submission history
From: Laura Mayorga
[v1] Mon, 24 Oct 2016 23:31:15 GMT (644kb) 

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