ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Numerous atomic lines appearing in the terrestrial nightglow can be measured by HIRES, the echelle spectrometer on the 10 meter Keck I telescope on Mauna Kea. The observable nightglow lines include emissions from Na, K, Hg, Ne, N, O, and H. Agreement between the line positions and those from National Institute of Science and Technology (NIST) compilations is excellent for well-known lines, typically 2 mÅ or better. For lines which are not well-known, or cannot be measured directly in the laboratory, deviations are significant. In particular, for the optically forbidden N(2D–4S) transition the differences are substantial, 20 and 24 mÅ for the two components. Apart from improving the line positions for this transition, we also correct an error that has been perpetuated in the aeronomic literature for the last 30 years concerning the transition wavelengths. The potassium D1 line, recently discovered in the HIRES sky spectra, exhibits a position difference of 11 mÅ between the NIST and HIRES values, significant for astronomical applications. The HIRES value is shown to be in close agreement with the latest laboratory study. For the Balmer series of H lines, we report the first ground-based observation of Hγ in the geocorona, and we confirm that the positions of the H(α,β,γ) lines agree with the expectation that the principal source is direct solar resonance excitation, with a 5%–6% cascading contribution in the case of Hα. The absolute average intensities of the three lines are 3600, 900, and ∼210 millirayleighs (mR), respectively. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1318195
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