New limits on H+(3) abundance on Neptune using Keck NIRSPEC.
MON NOT R ASTRON SOC
641 - 644.
Neptune and Uranus are observed with Keck II NIRSPEC in an attempt to detect H+(3) emission from Neptune. In this set of observations, H+(3) emission remains undetected at Neptune, whereas line-resolved emission from Uranus was observed with a signal-to-noise ratio of similar to 100. Using this, we have derived an upper limit of the column-integrated H+(3) density on Neptune of 1.5 (+4.8(-0.9))x 1013 m-2, assuming a temperature of 550 +/- 100 K. This value improves the previous established limit by a factor of 20 and shows that the H+(3) density predicted by the best available model overestimate the density by at least a factor of 3.In addition, the solar reflection continuum of Neptune in the K and L' bands is seen to be brighter on the Northern hemisphere by a factor of similar to 2, whereas previous observations had noted the solar reflection as being brighter on the Southern hemisphere.
|Title:||New limits on H+(3) abundance on Neptune using Keck NIRSPEC|
|Keywords:||techniques: spectroscopic, planets and satellites: atmospheres, planets and satellites: aurorae, planets and satellites: composition, planets and satellites: individual: Uranus, planets and satellites: individual: Neptune, ULTRAVIOLET SPECTROMETER OBSERVATIONS, H-3(+) EMISSION, URANUS, TEMPERATURE, SATURN, ATMOSPHERE, MOLECULE, JUPITER, AURORA, H-3+|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Science and Technology Studies|
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