08/03/2017
By Edwin L. Aguirre

UMass Lowell researchers will take advantage of the rare opportunity presented by the total solar eclipse on Aug. 21 to study how the moon’s shadow might affect Earth’s upper atmosphere.

Physics Prof. Supriya Chakrabarti, who directs the university’s Lowell Center for Space Science and Technology (LoCSST), hopes the data will help scientists better understand the impact of “space weather” – the constantly changing environmental conditions in interplanetary space, especially between the sun’s atmosphere, called the corona, and Earth’s outer atmosphere, called the ionosphere.

“Inclement space weather can affect GPS navigation, shortwave radio, satellite communications and much more,” explains Chakrabarti.

“During the eclipse, the moon’s shadow will sweep over the atmosphere at supersonic speed. It has been suggested that the passage of the shadow can create a wave similar to the one that forms at the bow of a ship as it moves through water,” he says. “Our goal is to record any potential disturbances in the upper atmosphere. We hope to observe the formation of a type of atmospheric wave, called ‘gravity wave,’ and determine how far and how deep these waves propagate.”

Chakrabarti, together with physics Asst. Prof. Timothy Cook, will operate an instrument – called the High-Throughput and Multi-slit Imaging Spectrometer, or HiT&MIS – at their observing site in Jackson, Wyo., where they will experience 2 minutes, 16 seconds of total eclipse.

The instrument, which was designed and built at LoCSST, will image a long, narrow vertical strip of sky at multiple optical wavelengths simultaneously and at high resolution to obtain a clear profile of the upper atmosphere.

“HiT&MIS can detect faint emissions from atoms and molecules such as oxygen, nitrogen and hydrogen,” says Susanna Finn, a research scientist at LoCSST who is the principal investigator for the center’s eclipse research, which is being supported by the National Science Foundation.

“HiT&MIS can observe these emissions during both daytime and nighttime, so during the eclipse, we can seamlessly observe changes in the atmosphere as the conditions go very quickly from daylight to darkness and back to daylight,” says Finn.   

To increase the chances of having clear skies on eclipse day, physics Ph.D. students and LoCSST research assistants Saurav Aryal and George Geddes will operate a similar instrument at a different site – the campus of Southern Illinois University (SIU) in Carbondale, which is close to the spot where the greatest duration of the total eclipse will occur: 2 minutes, 40 seconds.

“Turning the sun off and on abruptly during the eclipse will allow us to test different models of the ionosphere,” says Geddes, who, like Aryal, has never witnessed a total solar eclipse before.

Aryal adds, “The instrument will operate autonomously. Our role is to monitor it continuously before, during and after the eclipse to make sure there are no technical glitches.”

Geddes and Aryal, who will also make poster and oral presentations about their experiment at an eclipse workshop at SIU, will analyze the data collected by HiT&MIS.

“Total solar eclipses do not happen often at a given location, and they occur even more rarely in a place conducive to deploying an instrument and conducting research,” says Finn. “The conditions produced by a total solar eclipse are quite unique, so we look forward to the opportunity to take advantage of such an event happening right here in the United States.”

An Eclipse Megamovie

About 125 miles east of where Chakrabarti and Cook will be stationed, Edwin Aguirre, who works as senior science writer in the Office of University Relations, and his wife, Imelda Joson, are leading a private expedition to photograph the event along the eclipse path’s central line near Riverton, Wyo., where totality will last 2 minutes, 24 seconds.

Aguirre and Joson will use super telephoto lenses, apochromatic telescopes and GPS-equipped digital SLR cameras to capture high-resolution images of the sun’s corona during totality.

The couple is taking part in the “Eclipse Megamovie” project, an initiative launched by Google and the University of California Berkeley in partnership with the Astronomical Society of the Pacific, Oregon State University, Foothill College, the High Altitude Observatory of the National Center for Atmospheric Research, Lick Observatory, the University of Colorado at Boulder, Williams College and the International Astronomical Union Working Group on Solar Eclipses. The project will aggregate still images of the eclipse from more than 1,000 volunteer photographers and amateur astronomers.

The goal is to compile multi-megapixel images of the corona and the so-called “diamond-ring” effect, taken along the entire eclipse track, and convert them into a high-definition animation of the total eclipse. The data set will help scientists study the dynamics of the sun’s inner corona in great detail and measure the size of the sun with better precision.

“This project will produce an expanded and continuous coverage of the total eclipse that far exceeds what any one photographer can record from a single location,” notes Aguirre.

Farther west, physics Asst. Prof. Silas Laycock and Prof. Paul Song will get to see the eclipse while attending astronomy meetings, although they are not planning to conduct any eclipse-related experiments. Laycock will be in Sun Valley, Idaho, for the gathering of the High Energy Astrophysics Division of the American Astronomical Society (AAS). Totality here is expected to last 1 minute, 12 seconds.

Song will be in Portland, Ore., for the AAS Solar Physics Division meeting, where he will present a paper about his research on a model of the chromosphere, the red-colored middle layer of the sun that will be visible during the total eclipse. Portland lies outside the eclipse path, so attendees will be transported by bus to Willamette University in Salem, where they will be treated to 1 minute, 54 seconds of totality.

Finn, for her part, is opting to simply sit back, relax and enjoy the celestial show. She will be with her family camping in Oregon’s Ochoco National Forest near Mitchell, where they be immersed in 2 minutes, 4 seconds of morning darkness.

“This will be my very first total solar eclipse, so I’m really excited,” says Finn.