U.S. Naval Research Laboratory (NRL) scientists continue to break ground using the Large Angle and Spectrometric Coronagraph (LASCO)
telescope. The telescope, which has been in operation for the past 27 years, is now collecting new information about the properties of asteroids and comets near the sun.
LASCO is one of 15 instruments on the joint NASA
/ESA Solar and Heliospheric Observatory
spacecraft, launched in December 1995 to study the sun from its interior to its dynamic atmosphere and corona and its interaction with the entire solar system. LASCO is a critical asset for heliophysics researchers that has revolutionized many areas of solar physics.
Scientists and agencies worldwide rely on LASCO for operational space weather monitoring and forecasting. Its uninterrupted data stream provides near real-time warning of potentially hazardous Earth-directed coronal mass ejections.
Now, LASCO's interchangeable imaging filters, which are sensitive to different wavelengths of light, are also being used to provide new insight into the chemical makeup of objects passing in front of its field of view and the processes they undergo as they experience extreme conditions in the near-sun environment.
“When a comet or asteroid gets close to the sun, the intense radiation environment can release a lot of sodium from the object's surface,” said Karl Battams, Ph.D., a computational scientist in NRL's Space Science Division and LASCO principal investigator. “We can use LASCOs filters to look for signatures of sodium or the presence of dust, helping us understand the processes occurring on the surface of the comet or asteroid.”
The environment near the sun is extraordinarily hostile to comets and asteroids. However, LASCO's unique ability to image the near-sun region allows for studying the behavior of otherwise essentially inert asteroids and comets as they undergo extreme physical and chemical processes.
In early 2022, Battams and CalTech Planetary Science Ph.D. Candidate Qicheng Zhang, a former NRL summer intern, devised a unique observing plan to leverage LASCO's capabilities, leading to a pivotal new result regarding near-sun asteroid Phaethon. Their study, soon to be published in the Planetary Science Journal
, overturns the widely-held belief that Phaethon produces a significant quantity of dust as it passes by the sun, instead finding it releases sodium. This is a substantial result regarding the asteroid that is set to be visited during a Japanese Aerospace Exploration Agency Destiny+
mission in 2028.
“Even after 27 years, we are still finding novel ways to get unique science out of LASCO,” said Battams. “It was never intended to study comets, yet with these recent observations, LASCO has upended years of belief about this asteroid and again demonstrated its unique worth.”
In February 2023, Zhang and Battams executed another successful LASCO-based observing plan for comet 96P/Machholz, whose dataset revealed a previously unknown debris trail
following the comet's orbit.
LASCO also plays a significant role in the NASA-funded and NRL-based Sungrazer Project
. Since 2003, the Sungrazer Project has been a NASA-funded citizen science program that enables the discovery and reporting of previously unknown comets in heliophysics imaging data, primarily the LASCO and NASA Solar Terrestrial Relations Observatory
(STEREO) observations. Images from these mission instruments provide data for citizen scientist “comet hunters” to search for new comets.
The project is responsible for discovering well over half of all officially documented comets and has led to numerous scientific publications looking at comet dynamics, evolution, composition, and more. Through these studies of the interaction between comets and the sun, scientists have gained new insights into the nature of the near-sun environment and solar outflows that drive space weather.
“Sungrazer is a citizen science project with global participation,” said Battams. “The countless hours of volunteered time and input from its participants continue to drive a wealth of unique science that simply could not be gathered by any other means.”
About the U.S. Naval Research Laboratory
NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL is located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.
For more information, contact NRL Corporate Communications at (202) 480-3746 or firstname.lastname@example.org