Instrument Will Observe the Sun-like Star Epsilon Eridani
By Edwin L. Aguirre
“Our goal is to use a NASA sounding rocket
to launch PICTURE-B to the very edge of the atmosphere so we can observe Epsilon Eridani in infrared and visible light,” says Chakrabarti.
— an orange dwarf star that is younger, fainter and slightly cooler and less massive than the Sun — is located 10 light-years away in the constellation Eridanus. It is the nearest planetary system to Earth, harboring one (or possibly two) planets as well as a pair of asteroid belts and a dust disk.
“We are going to directly measure the visible light scattered by the debris disk around Epsilon Eridani,” explains Cook. “If successful, the PICTURE-B mission would help advance the design of future space telescopes for the direct imaging of exoplanets. Our project’s ultimate goal is to discover Earth-like planets around sun-like stars capable of supporting life.”
PICTURE-B, which stands for Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base, features a visible nulling coronagraph instrument, or “nuller,” a specialized optical imaging system coupled to a telescope with a primary mirror 22 inches in diameter
. The nuller is designed to “mask,” or block out, the overwhelmingly bright light from Epsilon Eridani so that faint objects very close to the star — such as planets, asteroids and interplanetary dust, which otherwise would be hidden in the star’s glare — can be investigated in great detail. The nuller and the telescope’s tracking system have successfully demonstrated their spaceflight-worthiness during a sounding-rocket launch in 2011 and are being flown again for this upcoming mission.
“The study of extrasolar planets is one of the most exciting endeavors of modern science,” notes Chakrabarti. “PICTURE-B will demonstrate that routine imaging of exoplanets can be accomplished at modest cost. This will have a profound impact on exoplanet research and can lead to a better understanding of the formation of planetary systems as well as our place in the universe.”
Chakrabarti and Cook are the project’s principal investigator and co-investigator, respectively. Other members of the UMass Lowell team are postdoctoral associate Christopher Mendillo, visiting researcher Ewan Douglas and mechanical engineer Jason Martel of the university’s Lowell Center for Space Science and Technology
(LoCSST), based in Wannalancit Mills on East Campus. The team is also collaborating with researchers from Boston University, Northrop-Grumman Inc. and NASA’s Goddard Space Flight Center.
“Our very dedicated students and research staff at LoCSST have been working hard to make sure that the experiment will perform as best as possible,” says Chakrabarti. “Jason is responsible for making sure that the components meet the required precise tolerances while being lightweight and rugged. Chris has checked and double-checked every subsystem, from optical components to the detectors and computers. He and Ewan, a doctoral student whose dissertation will incorporate data from this experiment, worked with many external partners, including AOA Xinetics, which fabricated the telescope mirror. They have also been working with NASA engineers who subjected the experiment to a battery of functional and environmental tests to verify that the instrument is ready to fly.”
Balloon Missions to the Threshold of Space
PICTURE-B will be launched aboard a Black Brant IX, an 18-foot-long, two-stage sounding rocket capable of carrying up to 1,200 pounds of payload into suborbital flight. However, this rocket is not powerful enough to boost the instrument to orbital speed — after about four minutes of scientific observation, the payload will fall back to Earth, deploying a parachute to slow down its descent and allow for a safe recovery of the payload on the ground.
After the mission is completed, PICTURE-B will be reconfigured so it can conduct extended observations of fainter, more distant debris disks around other stars using large helium balloons that would carry the instrument high into the stratosphere.
“This next mission, which will be designated as PICTURE-C, will allow us to take longer, deeper images of a number of nearby target stars, including Alpha Lyrae and Beta Leonis,” says Cook.
Last year, NASA awarded Chakrabarti and his LoCSST team a five-year grant worth nearly $5.6 million
for the project. PICTURE C is scheduled to be launched on two separate flights, in the fall of 2017 and 2019, from the Columbia Scientific Balloon Facility in Fort Sumner, N.M.