The time variation of atomic oxygen emission around Io during a volcanic event observed with Hisaki/EXCEED

Ryoichi Koga, Fuminori Tsuchiya, Masato Kagitani, Takeshi Sakanoi, Mizuki Yoneda, Kazuo Yoshioka, Tomoki Kimura, Go Murakami, Atsushi Yamazaki, Ichiro Yoshikawa, H. Todd Smith

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Io has an atmosphere produced by volcanism and sublimation of frosts deposited around active volcanoes. However, the time variation of atomic oxygen escaping Io's atmosphere is not well known. In this paper, we show a significant increase in atomic oxygen around Io during a volcanic event. Brightening of Io's extended sodium nebula was observed in the spring of 2015. We used the Hisaki satellite to investigate the time variation of atomic oxygen emission around Io during the same period. This investigation reveals that the duration of atomic oxygen brightness increases from a volcanically quiet level to a maximum level during the same approximate time period of 30 days as the observed sodium brightness. On the other hand, the recovery of the atomic oxygen brightness from the maximum to the quiet level (60 days) was longer than that of the sodium nebula decreasing (40 days). Additionally, a dawn-dusk asymmetry of the atomic oxygen emission is observed.

Original languageEnglish
Pages (from-to)300-307
Number of pages8
JournalIcarus
Volume299
DOIs
Publication statusPublished - 2018 Jan 1

Keywords

  • Atomic oxygen
  • Io
  • Neutral cloud
  • Volcanism

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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