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Line Profile Measurements of the Lunar Exospheric SodiumWe report ongoing results of a program to measure the lunar sodium exospheric line profile from near the lunar limb out to two lunar radii (approx 3500 km). These observations are conducted from the National Solar Observatory McMath-Pierce telescope using a dual-etalon Fabry-Perot spectrometer with a resolving power of 180,600 (1.7 km/s) to measure line widths and velocity shifts of the Na D2 (5889 950 A) emission line in equatorial and polar regions at different lunar phases. The typical field of view (FOV) is 3 arcmin (approx 360 km) with an occasional smaller 1 arcmin FOV used right at the limb edge. The first data were obtained from full Moon to 3 days following full Moon (waning phase) in March 2009 as part of a demonstration run aimed at establishing techniques for a thorough study of temperatures and velocity variations in the lunar sodium exosphere. These data indicate velocity displacements from different locations off the lunar limb range between 150 and 600 m/s from the lunar rest velocity with a precision of +/- 20 to +/- 50 m/s depending on brightness. The measured Doppler line widths for observations within 10.5 arcmin of the east and south lunar limbs for observations between 5 deg and 40 deg lunar phase imply temperatures ranging decreasing from 3250 +/- 260K to 1175 +/- 150K. Additional data is now being collected on a quarterly basis since March 2011 and preliminary results will be reported.
Document ID
20120016371
Document Type
Conference Paper
Authors
Oliversen, Ronald J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mierkiewicz, Edwin J. (Wisconsin Univ. WI, United States)
Line, Michael R. (California Inst. of Tech. Pasadena, CA, United States)
Roesler, Fred L. (Wisconsin Univ. WI, United States)
Lupie, Olivia L. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 26, 2013
Publication Date
July 2, 2012
Subject Category
Lunar and Planetary Science and Exploration
Report/Patent Number
GSFC.ABS.7441.2012
Meeting Information
Lunar Science Forum 2012(Moffett Field, CA)
Distribution Limits
Public
Copyright
Other