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The spectrum of the Jovian aurora 1150–1700 Å
Author(s) -
Durrance Samuel T.,
Feldman Paul D.,
Moos H. Warren
Publication year - 1982
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/gl009i006p00652
Subject(s) - jovian , jupiter (rocket family) , physics , spectrograph , wavelength , spectral line , astrophysics , spectral resolution , planet , astronomy , optics , saturn , space shuttle
A series of observations of the northern hemisphere of Jupiter was made in January 1981 using the International Ultraviolet Explorer short‐wavelength spectrograph. Exposures of 15 minutes each were made at regular intervals of about 45 minutes around the time when Jupiter's north magnetic pole was tilted toward the Earth. The auroral emissions of H Lyman‐α, and the H 2 Lyman‐ and Werner‐bands are seen to emanate from a localized region near the north pole. Their intensity increases and decreases in a periodic way as the planet rotates with the maximum occuring at λ III ∼185°. Using the three observations nearest the observed maximum, a composite spectrum of the aurora is obtained with about 8 Å resolution and high signal‐to‐noise ratio, and many of the H 2 Lyman‐ and Werner‐bands in this spectral region (1150–1700 Å) are identified. This spectrum is compared with a laboratory H 2 spectrum and with photoabsorption cross sections for CH 4 and C 2 H 6 . An upper limit to the slant column density of these hydrocarbons above the auroral emissions is found to be ∼ 2×10 17 cm −2 .