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Neptune's deep atmosphere revealed
Author(s) -
Romani Paul N.,
de Pater Imke,
Atreya Sushil K.
Publication year - 1989
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/gl016i008p00933
Subject(s) - neptune , uranus , brightness , mixing ratio , atmosphere (unit) , physics , brightness temperature , astronomy , astrophysics , wavelength , planet , atmospheric sciences , optics , meteorology
The brightness temperature of Uranus at 20 cm is 260 ± 10K, while for Neptune it is 318 ± 16K. Since NH 3 is the dominant absorber at this wavelength we have modeled the microwave spectra of Neptune based upon an assumed deep gaseous mixing ratio of NH 3 and subsequent loss into clouds. The difference between the two brightness temperatures implies that the NH 3 mixing ratio below the level of cloud formation on Neptune compared to Uranus is lower by nearly 2 orders of magnitude. An alternative explanation is that the 20 cm radiation from Neptune is a combination of thermal plus synchrotron emission as proposed by de Pater and Goertz [1989].