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Coronagraphic Observations of the Lunar Sodium Exosphere January-June, 2017In order to observe the lunar sodium exosphere out to one-half degree around the Moon, we designed, built and installed a small robotically controlled coronagraph at the Winer Observatory in Sonoita, Arizona. Observations are obtained remotely every available clear night from our home base at Goddard Space Flight Center or from Prescott, Arizona. We employ an Andover temperature-controlled 1.5-angstrom-wide narrow-band filter centered on the sodium D2 line, and a similar 1.5-angstrom filter centered blueward of the D2 line by 3 angstroms for continuum observations. Our data encompass lunations in 2015, 2016, and 2017, thus we have a long baseline of sodium exospheric calibrated images. During the course of three years we have refined the observational sequence in many respects. Therefore this paper only presents the results of the spring, 2017, observing season. We present limb profiles from the south pole to the north pole for many lunar phases. Our data do not fit any power of cosine model as a function of lunar phase or with latitude. The extended Na exosphere has a characteristic temperature of about 2250–6750 degrees Kelvin, indicative of a partially escaping exosphere. The hot escaping component may be indicative of a mixture of impact vaporization and a sputtered component.
Document ID
20190025174
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Killen, Rosemary M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Morgan, Thomas H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Potter, Andrew E.
(National Solar Observatory Boulder, CO, United States)
Plymate, Claude
(California Institute of Technology Pasadena, CA, United States)
Tucker, Roy
(Arizona Univ. Tucson, AZ, United States)
Johnson, Jamil D.
(Howard Univ. Washington, DC, United States)
Date Acquired
May 16, 2019
Publication Date
March 16, 2019
Publication Information
Publication: Icarus
Publisher: Elsevier
Volume: 328
ISSN: 0019-1035
e-ISSN: 1090-2643
Subject Category
Astronomy
Report/Patent Number
GSFC-E-DAA-TN68105
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Keywords
Moon
Structure
Atmospheres
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