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Title: REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLE IBEX POINTING STRATEGY

Abstract

The Interstellar Boundary Explorer (IBEX) has observed the interstellar neutral (ISN) gas flow over the past 6 yr during winter/spring when the Earth’s motion opposes the ISN flow. Since IBEX observes the interstellar atom trajectories near their perihelion, we can use an analytical model based upon orbital mechanics to determine the interstellar parameters. Interstellar flow latitude, velocity, and temperature are coupled to the flow longitude and are restricted by the IBEX observations to a narrow tube in this parameter space. In our original analysis we found that pointing the spacecraft spin axis slightly out of the ecliptic plane significantly influences the ISN flow vector determination. Introducing the spacecraft spin axis tilt into the analytical model has shown that IBEX observations with various spin axis tilt orientations can substantially reduce the range of acceptable solutions to the ISN flow parameters as a function of flow longitude. The IBEX operations team pointed the IBEX spin axis almost exactly within the ecliptic plane during the 2012–2014 seasons, and about 5° below the ecliptic for half of the 2014 season. In its current implementation the analytical model describes the ISN flow most precisely for the spin axis orientation exactly in the ecliptic. This analysismore » refines the derived ISN flow parameters with a possible reconciliation between velocity vectors found with IBEX and Ulysses, resulting in a flow longitude λ{sub ∞} = 74.°5 ± 1.°7 and latitude β{sub ∞} = −5.°2 ± 0.°3, but at a substantially higher ISN temperature than previously reported.« less

Authors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
22522471
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 804; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; DATA ANALYSIS; GAS FLOW; HELIOSPHERE; INTERSTELLAR SPACE; ORIENTATION; SPACE VEHICLES; SPIN; SUN; TRAJECTORIES; VECTORS; VELOCITY

Citation Formats

Leonard, T. W., Möbius, E., Heirtzler, D., Kucharek, H., Lee, M. A., Schwadron, N. A., E-mail: twp5@wildcats.unh.edu, E-mail: eberhard.moebius@unh.edu, E-mail: dheirtzl@atlas.sr.unh.edu, E-mail: harald.kucharek@unh.edu, E-mail: marty.lee@unh.edu, E-mail: nathan.schwadron@unh.edu, and others, and. REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLE IBEX POINTING STRATEGY. United States: N. p., 2015. Web. doi:10.1088/0004-637X/804/1/42.
Leonard, T. W., Möbius, E., Heirtzler, D., Kucharek, H., Lee, M. A., Schwadron, N. A., E-mail: twp5@wildcats.unh.edu, E-mail: eberhard.moebius@unh.edu, E-mail: dheirtzl@atlas.sr.unh.edu, E-mail: harald.kucharek@unh.edu, E-mail: marty.lee@unh.edu, E-mail: nathan.schwadron@unh.edu, & others, and. REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLE IBEX POINTING STRATEGY. United States. doi:10.1088/0004-637X/804/1/42.
Leonard, T. W., Möbius, E., Heirtzler, D., Kucharek, H., Lee, M. A., Schwadron, N. A., E-mail: twp5@wildcats.unh.edu, E-mail: eberhard.moebius@unh.edu, E-mail: dheirtzl@atlas.sr.unh.edu, E-mail: harald.kucharek@unh.edu, E-mail: marty.lee@unh.edu, E-mail: nathan.schwadron@unh.edu, and others, and. Fri . "REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLE IBEX POINTING STRATEGY". United States. doi:10.1088/0004-637X/804/1/42.
@article{osti_22522471,
title = {REVISITING THE ISN FLOW PARAMETERS, USING A VARIABLE IBEX POINTING STRATEGY},
author = {Leonard, T. W. and Möbius, E. and Heirtzler, D. and Kucharek, H. and Lee, M. A. and Schwadron, N. A., E-mail: twp5@wildcats.unh.edu, E-mail: eberhard.moebius@unh.edu, E-mail: dheirtzl@atlas.sr.unh.edu, E-mail: harald.kucharek@unh.edu, E-mail: marty.lee@unh.edu, E-mail: nathan.schwadron@unh.edu and others, and},
abstractNote = {The Interstellar Boundary Explorer (IBEX) has observed the interstellar neutral (ISN) gas flow over the past 6 yr during winter/spring when the Earth’s motion opposes the ISN flow. Since IBEX observes the interstellar atom trajectories near their perihelion, we can use an analytical model based upon orbital mechanics to determine the interstellar parameters. Interstellar flow latitude, velocity, and temperature are coupled to the flow longitude and are restricted by the IBEX observations to a narrow tube in this parameter space. In our original analysis we found that pointing the spacecraft spin axis slightly out of the ecliptic plane significantly influences the ISN flow vector determination. Introducing the spacecraft spin axis tilt into the analytical model has shown that IBEX observations with various spin axis tilt orientations can substantially reduce the range of acceptable solutions to the ISN flow parameters as a function of flow longitude. The IBEX operations team pointed the IBEX spin axis almost exactly within the ecliptic plane during the 2012–2014 seasons, and about 5° below the ecliptic for half of the 2014 season. In its current implementation the analytical model describes the ISN flow most precisely for the spin axis orientation exactly in the ecliptic. This analysis refines the derived ISN flow parameters with a possible reconciliation between velocity vectors found with IBEX and Ulysses, resulting in a flow longitude λ{sub ∞} = 74.°5 ± 1.°7 and latitude β{sub ∞} = −5.°2 ± 0.°3, but at a substantially higher ISN temperature than previously reported.},
doi = {10.1088/0004-637X/804/1/42},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 804,
place = {United States},
year = {2015},
month = {5}
}