AAO Colloquium


Friday 16 July 2004

3:30pm AAO Conference Room

Aeronomy by Astronomy

Tom Slanger,   Molecular Physics Laboratory, SRI International

The terrestrial nightglow is found at altitudes above 80 km, and can be viewed as the relaxation and re-constitution of the atmosphere following solar-induced processes such as photodissociation and photoionization. Because molecular oxygen is a principal photoabsorber, much of the nightglow involves emission from atomic and molecular oxygen. These emitters are invariably metastable with respect to radiation, and therefore the atmosphere is often found to be a more benign environment than the laboratory for studying these species.

Over the last few years, we have found that so-called sky spectra from large telescopes are a marvelous tool for studying the nightglow. In this presentation, the technique will be described, and applied to studies on the Atmospheric Band system of O2 in the mesosphere and the ionosphere, the radiative recombination of O+ in the ionosphere, and the mysterious variability of the mesospheric sodium nightglow D2/D1 line ratio.

References
1. Slanger, T.G., et al., The Isotopic Oxygen Nightglow as Viewed From Mauna Kea. Science, 1997. 277: p. 1485-1488.
2. Osterbrock, D.E., et al., Faint OH(v = 10), 17OH, and 18OH lines in the spectrum of the night airglow. Publ. Astron. Soc. Pac., 1998. 110: p. 1499-1510.
3. Slanger, T.G. and D.E. Osterbrock, Investigation of potassium, lithium, and sodium emissions in the nightglow, and OH cross-calibration. Journal of Geophysical Research, 2000. 105: p. 1425-1429.
4. Slanger, T.G., et al., Vibrational Level Distribution of O2(b1g+, = 0-15) in the Mesosphere and Lower Thermosphere Region. Journal of Geophysical Research, 2000. 105: p. 20557-20564.
5. Slanger, T.G., et al., Accurate Atomic Line Wavelengths from Astronomical Sky Spectra. Journal of Chemical Physics, 2000. 113: p. 8514-8520.
6. Osterbrock, D.E., et al., Faint Emission Lines in the Blue and Red Spectral Regions of the Night Airglow. Publications of the Astronomical Society of the Pacific, 2000. 112: p. 733-741.
7. Slanger, T.G., et al., Discovery of the Atomic Oxygen Green Line in the Venus Night Airglow. Science, 2001. 291: p. 463-465.
8. Slanger, T.G., et al., Nightglow Studies with the World's Largest Optical Telescope. Advances in Space Research, 2001. 27: p. 1135-1145.
9. Slanger, T.G. and B.C. Wolven, Airglow Processes in Planetary Atmospheres, in Atmospheres in the Solar System: Comparative Aeronomy, M. Mendillo, A. Nagy, and J.H. Waite, Editors. 2002, American Geophysical Union: Washington D.C.
10. Slanger, T.G., P.C. Cosby, and D.L. Huestis, A new O2 band system: The c1-u - b1+g transition in the terrestrial nightglow. Journal of Geophysical Research, 2003. 108(A2): p. 1089.
11. Slanger, T.G., et al., The high-resolution light-polluted night-sky spectrum at Mt. Hamilton, California. Publications of the Astronomical Society of the Pacific, 2003. 115: p. 869-878.
12. Slanger, T.G., P.C. Cosby, and D.L. Huestis, Ground-based observation of high-altitude high-temperature emission in the O2 Atmospheric band nightglow. Journal of Geophysical Research, 2003. 108(A7): p. 10.1029/2003JA009885.
13. Slanger, T.G. and R.A. Copeland, Energetic Oxygen in the Upper Atmosphere and the Laboratory. Chemical Reviews, 2003. 103(12): p. 4731-4765.
14. Slanger, T.G., P.C. Cosby, and D.L. Huestis, Co-variation of Nightglow Emission from the O2(A3+u ) and O2(c1-u ) States and the Oxygen Green Line, Observed with the Keck I/II Telescopes. Journal of Atmospheric and Solar-Terrestrial Physics, 2004. 66(6-9): p. 617-622.
15. Sharpee, B.D., et al., Measurements of the Singly-Ionized Oxygen Auroral Doublet Lines ll7320,7330 using High-Resolution Sky Spectra. The Astrophysical Journal, 2004. 606: p. 605-610.