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H_2 fluorescence spectrum from 1200 to 1700 Å by electron impact: Laboratory study and application to Jovian aurora

Yung, Yuk L. and Gladstone, G. Randall and Chang, Kar Man and Ajello, Joseph M. and Srivastava, S. K. (1982) H_2 fluorescence spectrum from 1200 to 1700 Å by electron impact: Laboratory study and application to Jovian aurora. Astrophysical Journal Letters, 254 (2). L65-L69. ISSN 2041-8205. http://resolver.caltech.edu/CaltechAUTHORS:20140905-115015917

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Abstract

A combined experimental study of the fluorescence spectrum of H_2 at wavelengths of 1200-1700 Å by electron impact and its application to modeling the Jovian aurora have been carried out. Our laboratory data suggest that at 100 eV the relative cross sections for direct excitation of Lyɑ, Lyman bands (B^1Σ_u^+-X^1Σ_g^+), and Werner bands (C^1π_u-X^1Σ_g^+) are 1, 2.3±0.6, and 2.6±0.5, respectively, in conflict with Stone and Zipfs (1972) results for the Werner bands. Cascade from E,F^1Σ_g^+ states contributes an additional 31% to the B^1Σ_u^+ state population. It is shown that the most likely fate for the metastable H(2^2S) atoms produced in the Jovian aurora is collisional quenching to H(2^2P), and this could add as much as 60% to the predicted Lyɑ emission. On the basis of detailed atmospheric and radiative transfer modeling, we conclude that the recent IUE and Voyager observations are consistent with precipitation of electrons with energy in the range of 1-30 keV or other energetic particles that penetrate to number densities of 4 X 10^(10)-5 X 10^(13) cm^(-3) or column densities of 5 X 10^(17)-2 X 10^(20) cm^(-2) in the atmosphere. The globally averaged energy flux and production of hydrogen atoms are 0.5-2 ergs cm^(-2) s^(-1) and 1-4 X 10^(10) atoms cm^(-2) s^(-1), respectively.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://adsabs.harvard.edu//abs/1982ApJ...254L..65YADSArticle
http://dx.doi.org/10.1086/183757DOIArticle
Alternate Title:H2 fluorescence spectrum from 1200 to 1700 Å by electron impact: Laboratory study and application to Jovian aurora
Additional Information:© 1982 American Astronomical Society. Provided by the NASA Astrophysics Data System. Received 1981 February 20; accepted 1981 November 20.
Subject Keywords:laboratory spectra, molecular processes, planets: atmospheres
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Caltech Division of Geological and Planetary Sciences 3570
Record Number:CaltechAUTHORS:20140905-115015917
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140905-115015917
Official Citation:H2 fluorescence spectrum from 1200 to 1700 A by electron impact - Laboratory study and application to Jovian aurora Yung, Y. L.; Gladstone, G. R.; Chang, K. M.; Ajello, J. M.; Srivastava, S. K. Astrophysical Journal, Part 2 - Letters to the Editor, vol. 254, Mar. 15, 1982, p. L65-L69. Publication Date: 03/1982
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49292
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:05 Sep 2014 22:00
Last Modified:22 Mar 2019 17:00

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