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Variation of Jupiter's aurora observed by Hisaki/EXCEED: 1. Observed characteristics of the auroral electron energies compared with observations performed using HST/STIS
Author(s) -
Tao Chihiro,
Kimura Tomoki,
Badman Sarah V.,
Murakami Go,
Yoshioka Kazuo,
Tsuchiya Fuminori,
André Nicolas,
Yoshikawa Ichiro,
Yamazaki Atsushi,
Shiota Daikou,
Tadokoro Hiroyasu,
Fujimoto Masaki
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2015ja021271
Subject(s) - physics , jupiter (rocket family) , brightness , wavelength , astrophysics , rotation period , longitude , astronomy , latitude , optics , stars , space shuttle
Temporal variation of Jupiter's northern aurora is detected using the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) on board JAXA's Earth‐orbiting planetary space telescope Hisaki. The wavelength coverage of EXCEED includes the H 2 Lyman and Werner bands at 80–148 nm from the entire northern polar region. The prominent periodic modulation of the observed emission corresponds to the rotation of Jupiter's main auroral oval through the aperture, with additional superposed −50%–100% temporal variations. The hydrocarbon color ratio (CR) adopted for the wavelength range of EXCEED is defined as the ratio of the emission intensity in the long wavelength range of 138.5–144.8 nm to that in the short wavelength range of 126.3–130 nm. This CR varies with the planetary rotation phase. Short‐ (within one planetary rotation) and long‐term (> one planetary rotation) enhancements of the auroral power are observed in both wavelength ranges and result in a small CR variation. The occurrence timing of the auroral power enhancement does not clearly depend on the central meridian longitude. Despite the limitations of the wavelength coverage and the large field of view of the observation, the auroral spectra and CR‐brightness distribution measured using EXCEED are consistent with other observations.