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NASA’s solar system boundary rider sheds light on our relationship to space

NASA’s Interstellar Boundary Explorer, or IBEX, mission has shed new light on how the solar system and its heliosphere – the magnetic bubble in which it resides – reacts with interstellar space.

IBEX uses energetic neutral atom imaging to examine the boundary and has created the first maps showing the interactions and how they change over time. 

Scientists have presented the achievements of IBEX in 14 papers published in the October 2015 Astrophysical Journal Supplement.

“Over the past six years, this fundamental work focused on our place in the solar system has become the gold standard for understanding our sun, our heliosphere and the interstellar environment around us,” said David McComas, principal investigator of the IBEX mission at the Southwest Research Institute, or SwRI, in San Antonio, Texas.

Eight papers highlight the interstellar helium measurements taken by IBEX and the joint European Space Agency and NASA Ulysses spacecraft, which launched in 1990.

These are the only two spacecraft to have directly measured the local interstellar flow of these helium atoms.

The studies resolved an inconsistency in the direction and temperature of the interstellar flow in the data gathered by Ulysses compared to those taken by IBEX. Both data sets now affirm that the local interstellar flow is significantly hotter than believed previously based on the Ulysses observations alone, and provide insight into the direction the heliosphere is moving through the local material in the galaxy, as well as how fast it is traveling.

Other papers examine aspects of determining the composition of interstellar particles, looking closely at oxygen, helium, and neon, as well as how those and other particles are effectively measured, while still more discuss analysis techniques and related theoretical considerations.

“Collectively, these papers represent a huge step forward in our understanding of the interstellar medium in the heliophysics community,” said McComas.

Initially a two-year mission, funding for IBEX has been extended to 2017, with the potential for mission extensions beyond that. 

“For a Small Explorer, the scientific output has been tremendous,” said Eric Christian, IBEX mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“These 14 new papers seven years after launch show just how exciting a mission this is.”

Bill Condie

Bill Condie

Bill Condie is a science journalist based in Adelaide, Australia.

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