Direct Detection of Interstellar Neutrals from Earth Orbit

Stephen A. Fuselier (fuselier@mail.spasci.com)
O. W. Lennartsson (lennartsson@spasci.com)
Arthur G. Ghielmetti (gmetti@cobra.spasci.com)
Lockheed Martin ATC, 3251 Hanover St., Palo Alto, CA 94304-1191

Michael R. Collier (mcollier@pop600)
Thomas E. Moore (Thomas.E.Moore@gsfc.nasa.gov)
David Simpson (david.simpson@gsfc.nasa.gov)
NASA/GSFC, Greenbelt, MD 20771

Jack Quinn (quinn@unhedi2.sr.unh.edu)
Eberhard Moebius (eberhard.moebius@unh.edu)
University of New Hampshire, Durham, NH 03824

Daniel Rucinski (rucinski@cbk.waw.pl)

P. Wurz (peter.wurz@soho.unibe.ch)
University of Bern, Bern, Switzerland

From December 2000 to early March 2001, the IMAGE Low Energy Neutral Atom (LENA) 
imager detected a temporally variable signal that had peak count rate in the 
direction of the velocity vector of the Earth around the Sun. The direction of 
arrival and the timing of the signal are consistent with interstellar neutrals 
whose motion through the solar system is altered by the gravitational attraction 
of the Sun. Energy and mass analysis suggest that interstellar neutral He is 
responsible for the signal in the instrument.  The velocity distribution, mass 
and energy analysis, and time history of the interstellar neutral signal are 
reviewed with emphasis on the implications these observations have for the 
source region outside solar system.

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Presented at the Fall AGU Meeting, San Francisco, CA, USA, 2001