New limits on H3+ abundance on Neptune using Keck NIRSPEC

H. Melin*, T. Stallard, S. Miller, M. B. Lystrup, L. M. Trafton, T. C. Booth, C. Rivers

*Corresponding author for this work

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16 Citations (Scopus)

Abstract

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 ∼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)× 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 ∼2, whereas previous observations had noted the solar reflection as being brighter on the Southern hemisphere.
Original languageEnglish
Pages (from-to)641-644
Number of pages4
JournalMonthly Notices of the Royal Astronomical Society
Volume410
Issue number1
DOIs
Publication statusPublished - Jan 2011
Externally publishedYes

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