Temporal variation of the Jovian H I Lyman alpha emission (1979-1986)

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA093iA01p00029· OSTI ID:6096489

Skinner, T E ^[1]; DeLand, M T; Ballester, G E; Coplin, K A; Feldman, P D; Moos, H W ^[2]

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1. Univ. of Colorado, Boulder (United States)
2. Johns Hopkins Univ., Baltimore, MD (United States)

Observations monitoring the long-term spatial and temporal behavior of the Jovian H I L{gamma}{alpha} emission have been made with the International Ultraviolet Explorer (IUE) observatory beginning in December 1978, and extending through December 1986. The hydrogen bulge region centered near {lambda}{sub III}=100{degrees} has been observed to be a persistent feature of the Jovian upper atmosphere throughout the period of the observations, which includes the maximum of solar cycle 21 and the current minimum in solar activity. New and previously unpublished measurements made since early 1982 show that the average brightness of both the bulge and nonbulge regions has varied with the long-term solar L{gamma} {alpha} output, which has decreased by a factor of {approximately}2 in this time frame. However, the bulge is {approximately}25% brighter on average and exhibits more short-term variability than the nonbulge region. The factor of {approximately}2 change in Jupiter's L{gamma} {alpha} brightness during the descending phase of solar cycle 21 in significantly less than the order of magnitude variability reported for the ascending phase of the same cycle. The IUE results are consistent with pure resonant scattering from an H column of {approximately}10{sup 17} cm{sup {minus}2} and indicate that no observable changes have taken place in the Jovian atomic hydrogen abundance or the average atmospheric conditions during the 8-year period since December 1978. If the electroglow process recently proposed for the outer planets plays a significant role in the long-term behavior of the Jovian L{gamma} {alpha} emission, the electroglow must also follow the solar cycle at L{gamma} {alpha}.

• OSTI ID: 6096489
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 93:A1; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

660000* -- Physics-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
BRIGHTNESS
ELECTROMAGNETIC RADIATION
ELEMENT ABUNDANCE
ELEMENTS
HYDROGEN
JUPITER PLANET
LYMAN LINES
MONITORING
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY ATMOSPHERES
PLANETS
RADIATIONS
SCATTERING
SOLAR CYCLE
ULTRAVIOLET RADIATION
VARIATIONS