AN ANALYTICAL MODEL OF INTERSTELLAR GAS IN THE HELIOSPHERE TAILORED TO INTERSTELLAR BOUNDARY EXPLORER OBSERVATIONS
Abstract
The stationary distribution of interstellar neutral gas in the heliosphere subject to solar gravity, solar radiation pressure, photoionization, and charge exchange is investigated analytically assuming ionization rates and radiation pressure that are proportional to R{sup 2}, where R is the heliocentric radius. The collisionless hyperbolic trajectories of the individual atoms including ionization losses are combined with Liouville's Theorem to construct the heliospheric phasespace distribution function of an interstellar gas species in the solar reference frame under the assumption that the distribution is a drifting Maxwellian at large distances from the Sun. The distribution is transformed to the Earth (essentially Interstellar Boundary Explorer (IBEX)) frame as a function of solar longitude. The expression is then tailored to the latitudinal scan of IBEX as a function of longitude using the fact that IBEX detects each atom close to perihelion in its hyperbolic orbit. The distribution is further adapted to IBEX by integrating the differential intensity over the entrance aperture solid angle of the IBEXLo collimator, and over energy to predict the IBEX count rate of helium. The major features of the predicted count rate are described, including a peak in longitude, a peak in latitude at each longitude, and the widths ofmore »
 Authors:

 Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)
 Space Research Centre, Polish Academy of Sciences, 00716 Warsaw (Poland)
 Engineering and Space Science Division, Southwest Research Institute, San Antonio, TX 78228 (United States)
 Publication Date:
 OSTI Identifier:
 22048039
 Resource Type:
 Journal Article
 Journal Name:
 Astrophysical Journal, Supplement Series
 Additional Journal Information:
 Journal Volume: 198; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 00670049
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APERTURES; ASTROPHYSICS; ATOMS; CHARGE EXCHANGE; COLLIMATORS; COMPARATIVE EVALUATIONS; COSMIC GASES; COUNTING RATES; DISTRIBUTION FUNCTIONS; GRAVITATION; HELIOSPHERE; HELIUM; INTERSTELLAR SPACE; ORBITS; PHASE SPACE; PHOTOIONIZATION; RADIATION PRESSURE; SOLAR RADIATION; SUN; VELOCITY
Citation Formats
Lee, Martin A, Kucharek, Harald, Moebius, Eberhard, Xian, Wu, Bzowski, Maciej, and McComas, David. AN ANALYTICAL MODEL OF INTERSTELLAR GAS IN THE HELIOSPHERE TAILORED TO INTERSTELLAR BOUNDARY EXPLORER OBSERVATIONS. United States: N. p., 2012.
Web. doi:10.1088/00670049/198/2/10.
Lee, Martin A, Kucharek, Harald, Moebius, Eberhard, Xian, Wu, Bzowski, Maciej, & McComas, David. AN ANALYTICAL MODEL OF INTERSTELLAR GAS IN THE HELIOSPHERE TAILORED TO INTERSTELLAR BOUNDARY EXPLORER OBSERVATIONS. United States. doi:10.1088/00670049/198/2/10.
Lee, Martin A, Kucharek, Harald, Moebius, Eberhard, Xian, Wu, Bzowski, Maciej, and McComas, David. Wed .
"AN ANALYTICAL MODEL OF INTERSTELLAR GAS IN THE HELIOSPHERE TAILORED TO INTERSTELLAR BOUNDARY EXPLORER OBSERVATIONS". United States. doi:10.1088/00670049/198/2/10.
@article{osti_22048039,
title = {AN ANALYTICAL MODEL OF INTERSTELLAR GAS IN THE HELIOSPHERE TAILORED TO INTERSTELLAR BOUNDARY EXPLORER OBSERVATIONS},
author = {Lee, Martin A and Kucharek, Harald and Moebius, Eberhard and Xian, Wu and Bzowski, Maciej and McComas, David},
abstractNote = {The stationary distribution of interstellar neutral gas in the heliosphere subject to solar gravity, solar radiation pressure, photoionization, and charge exchange is investigated analytically assuming ionization rates and radiation pressure that are proportional to R{sup 2}, where R is the heliocentric radius. The collisionless hyperbolic trajectories of the individual atoms including ionization losses are combined with Liouville's Theorem to construct the heliospheric phasespace distribution function of an interstellar gas species in the solar reference frame under the assumption that the distribution is a drifting Maxwellian at large distances from the Sun. The distribution is transformed to the Earth (essentially Interstellar Boundary Explorer (IBEX)) frame as a function of solar longitude. The expression is then tailored to the latitudinal scan of IBEX as a function of longitude using the fact that IBEX detects each atom close to perihelion in its hyperbolic orbit. The distribution is further adapted to IBEX by integrating the differential intensity over the entrance aperture solid angle of the IBEXLo collimator, and over energy to predict the IBEX count rate of helium. The major features of the predicted count rate are described, including a peak in longitude, a peak in latitude at each longitude, and the widths of the major peak in both latitude and longitude. Analytical formulae for these features are derived for comparison with IBEX observations in order to determine the temperature and bulk velocity of the gas in interstellar space. Based in part on these formulae, the results for helium are presented in the companion paper by Moebius et al.},
doi = {10.1088/00670049/198/2/10},
journal = {Astrophysical Journal, Supplement Series},
issn = {00670049},
number = 2,
volume = 198,
place = {United States},
year = {2012},
month = {2}
}