An Analysis of the Voyager 2 Ultraviolet Spectrometer Occultation Data at Uranus: Inferring Heat Sources and Model Atmospheres
✍ Scribed by Michael H. Stevens; Darrell F. Strobel; Floyd Herbert
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 803 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0019-1035
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✦ Synopsis
The Voyager 2 Ultraviolet Spectrometer (UVS) stellar and solar occultation data obtained at Uranus have been analyzed to infer smooth thermospheric temperature profiles and heat source characteristics. Temperatures inferred in the upper thermosphere from these occultations are much higher ((850 \pm 100 \mathrm{~K})) than can be explained by solar extreme ultraviolet heating alone. Our analysis yields one heat source peaking at (\sim 1 \times 10^{-5} \mu) bar (range (8 \times) (10^{-7}-2 \times 10^{-5} \mu) bar) with an integrated heating rate of approximately (0.06(+0.02,-0.04) \mathrm{erg} \mathrm{cm}^{-2} \mathrm{sec}^{-1}) as the least-squares best fit to all occultation data. The best inferred temperature for the stellar entrance occultation (\left(63.7^{\circ} \mathrm{S}\right)) is at least (50 \mathrm{~K}) cooler near (50 \mu) bar than for the stellar exit occultation (\left(69.7^{\circ} \mathrm{N}\right)), whereas at about (0.1 \mu) bar this temperature contrast is less than (10 \mathrm{~K}). A constant temperature on pressure surfaces at low altitudes, however, cannot be excluded by the data. 1993 Academic Press, Inc.