Premium
Discovery of a longitudinal asymmetry in the H Lyman‐alpha brightness of Jupiter
Author(s) -
Sandel B. R.,
Broadfoot A. L.,
Strobel D. F.
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i001p00005
Subject(s) - longitude , jovian , physics , jupiter (rocket family) , atmosphere of jupiter , astronomy , planet , brightness , astrophysics , atmosphere (unit) , latitude , bulge , atmospheric sciences , saturn , meteorology , stars , spacecraft
A strong longitude variation in the midlatitude H Lyman α brightness of Jupiter has been discovered using data from the Voyager ultraviolet spectrometers. A minimum brightness of 14.4 kR was observed in the System III [1965] west longitude range 200°‐300°. The intensity rises to a broad peak of 19.6 kR near a longitude of 110°, a 36% increase over the minimum. This intensity "bulge" was observed to rotate with the planet and appeared at the same longitude during both Voyager encounters, four months apart. This is a surprising discovery; no other planet studied to date has such a characteristic and the upper levels of the Jovian atmosphere were expected to be uniform in longitude. It is likely that a longitudinal asymmetry in charged particle precipitation leads to selective heating of the upper atmosphere and increased dissociation of H 2 , increasing the hydrogen column abundance. The resulting increase in resonant scattering could produce the observed intensity bulge.