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UH Eclipse Expedition Finds Cool Gas in the Desert
A team from UH's Institute for Astronomy has just returned from an expedition to the blistering Sahara desert, where they found an unexpected source of cool gas—in the outer regions of the Sun.
The group traveled from Hawaii to Libya to observe the March 29 total solar eclipse—a rare event in which the bright disk of the Sun is obscured by the Moon for a few minutes. They took hundreds of pounds of scientific equipment, including three new instruments specially designed to study the Sun's outer corona, a region that is visible from the Earth only during a total solar eclipse.
Astronomer Jeff Kuhn stated, "Despite the daunting complexity of running a series of infrared and visible instruments from the middle of the Sahara, in the final analysis, it was the right choice—the weather and observing conditions were superb."
His colleague and expedition organizer Shadia Habbal added, "We received enormous assistance from the people of Libya, and could not have succeeded without their support."
Preliminary analysis of the expedition's observations show there was an enormous magnetic bubble that was erupting during the eclipse. With their sensitive infrared instruments, the team also discovered that the solar corona, long known to have a temperature of several million degrees, also contains a surprising amount gas that is hundreds of times cooler.
These observations open the door for refined measurements of the corona's elusive magnetic field using large telescopes like the Advanced Technology Solar Telescope, which may be built on Haleakala on Maui.
The group from the IfA also included astronomers Don Mickey and Ilia Roussev, postdoctoral fellow Huw Morgan, and graduate student Sarah Jaeggli. They established a camp deep in the Libyan Sahara desert along the centerline of the eclipse path with collaborators from Colorado (Judd Johnson), Appalachian State University in North Carolina (Adrian Daw), and Bridgewater State College in Massachusetts (Martina Arndt).
Figure 1: Judd Johnson and Shadia Habbal with two of the CCD cameras used to observe the eclipse.
Figure 2: Team members set up their camp in the Sahara. From left to right: Jeff Kuhn, Huw Morgan, Don Mickey (standing), Martina Arndt (squatting), Sarah Jaeggli, and Judd Johnson.
Figure 3: Jeff Kuhn prepares a dewar (a high-tech thermos bottle) by filling it with liquid nitrogen (–321 degrees F/–196 degrees C) to keep infrared instruments cool enough to function properly during the eclipse observations.
Figure 4: The IfA eclipse team (top row from left to right) Huw Morgan, Sarah Jaeggli, Judd Johnson, Shadia Habbal, Martina Arndt, (bottom) Adrian Daw, Jeff Kuhn, Ilia Roussev, and Don Mickey.
Figure 5: While the disk of the Sun was eclipsed by the Moon, the solar corona looked like flames emerging from the Sun's surface in this image taken by the UH eclipse expedition to the Sahara desert.
The Institute for Astronomy at the University of Hawaii conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea.
Established in 1907 and fully accredited by the Western Association of Schools and Colleges, the University of Hawaii is the state's sole public system of higher education. The UH System provides an array of undergraduate, graduate, and professional degrees and community programs on 10 campuses and through educational, training, and research centers across the state. UH enrolls more than 50,000 students from Hawaii, the U.S. mainland, and around the world.