Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A New Technique to Investigate Jovian Upper Atmosphere

K. Tsumura, K. Arimatsu, E. Egami, Y. Hayano, C. Honda, J. Kimura, K. Kuramoto, S. Matsuura, Y. Minowa, K. Nakajima, T. Nakamoto, M. Shirahata, J. Surace, Y. Takahashi, T. Wada

Research output: Contribution to journalArticle

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Abstract

Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10-6-10-7 of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

Original languageEnglish
Article number122
JournalAstrophysical Journal
Volume789
Issue number2
DOIs
Publication statusPublished - Jul 10 2014

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Galilean satellites
upper atmosphere
Jupiter
Ganymede
near infrared
brightness
Europa
Jupiter (planet)
sunlight
Callisto
luminosity
haze
field of view
atmospheric composition
Space Infrared Telescope Facility
eclipses
planet
transit
spectroscopy
Hubble Space Telescope

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow : A New Technique to Investigate Jovian Upper Atmosphere. / Tsumura, K.; Arimatsu, K.; Egami, E.; Hayano, Y.; Honda, C.; Kimura, J.; Kuramoto, K.; Matsuura, S.; Minowa, Y.; Nakajima, K.; Nakamoto, T.; Shirahata, M.; Surace, J.; Takahashi, Y.; Wada, T.

In: Astrophysical Journal, Vol. 789, No. 2, 122, 10.07.2014.

Research output: Contribution to journalArticle

Tsumura, K, Arimatsu, K, Egami, E, Hayano, Y, Honda, C, Kimura, J, Kuramoto, K, Matsuura, S, Minowa, Y, Nakajima, K, Nakamoto, T, Shirahata, M, Surace, J, Takahashi, Y & Wada, T 2014, 'Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A New Technique to Investigate Jovian Upper Atmosphere', Astrophysical Journal, vol. 789, no. 2, 122. https://doi.org/10.1088/0004-637X/789/2/122
Tsumura, K. ; Arimatsu, K. ; Egami, E. ; Hayano, Y. ; Honda, C. ; Kimura, J. ; Kuramoto, K. ; Matsuura, S. ; Minowa, Y. ; Nakajima, K. ; Nakamoto, T. ; Shirahata, M. ; Surace, J. ; Takahashi, Y. ; Wada, T. / Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow : A New Technique to Investigate Jovian Upper Atmosphere. In: Astrophysical Journal. 2014 ; Vol. 789, No. 2.
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