NASA awarded the 麻豆原创 (which manages the site on behalf of National Science Foundation) the four-year grant to observe and characterize near-Earth objects (NEO) that pose a potential hazard to Earth or that could be candidates for future space missions.

The observatory is home to the most powerful and most sensitive planetary radar system in the world, which means it is also a unique tool available to analyze NEOs, such as asteroids and comets. The knowledge helps NASA determine which objects pose significant risks and when and what to do to mitigate them. NASA officials can also use the information to determine which objects are the most viable for science missions 鈥� landing on an asteroid is not equally easy for all of them. Information the observatory provided about asteroid Bennu, for example, is one of the factors that led NASA to select the OSIRIS-REx mission for funding.

麻豆原创 manages the NSF facility under a cooperative agreement with Universidad Ana G. M茅ndez and Yang Enterprises, Inc. The NASA grant will be used for operations, maintenance and upgrades to the radar system that directly relate to the Arecibo Planetary Radar Group, which leads this work. The group will spend up to 800 hours a year analyzing NEOs during the grant period.

The award also includes money to support STEM education among high school students in Puerto Rico. The Science, Technology And Research (STAR) Academy brings together 30 local high-school students per semester once a week for 16 classes to learn about science and research at the observatory.

鈥淭he S-band planetary radar system on the 305-m William E. Gordon telescope at Arecibo Observatory is the most sensitive planetary radar system in the world,鈥� says the Arecibo planetary radar program鈥檚 principal investigator Anne Virkki. She received her doctorate degree in astronomy from the University of Helsinki, Finland, and leads the planetary radar group at the observatory. 鈥淭his is why Arecibo is such an amazing tool for our work. Our radar astrometry and characterization are critical for identifying objects that are truly hazardous to Earth and for the planning of mitigation efforts. We can use our system to constrain the size, shape, mass, spin state, composition, binarity, trajectory, and gravitational and surface environments of NEOs and this will help NASA to determine potential targets for future missions.鈥�

Arecibo has played a role in analyzing NEOs since the mid-90s, observing 60-120 objects per year. Congress made NEOs a priority when it directed NASA in 2005 to seek out and characterize at least 90 percent of near-Earth objects larger than 140 meters by 2020.

鈥淎recibo plays an important role in discovery and advancing our knowledge of our solar system and our universe,鈥� says Francisco Cordova, director of the facility. 鈥淲e also play a critical role in helping to protect our planet through providing knowledge and unique expertise. It鈥檚 part of our mission and one of the reasons we are so passionate about our work.鈥�

The international team of asteroid observers at the observatory includes: Flaviane Venditti from Brazil; Sean Marshall from the U.S.; Dylan Hickson from Canada, and Luisa Zambrano-Marin from Colombia. Co-investigators include Noemi Pinilla-Alonso from the Florida Space Institute; Yanga Fernandez from 麻豆原创; Patrick Taylor and Edgard Rivera-Valentin from the Lunar and Planetary Institute; Michael Nolan and Ellen Howell from the University of Arizona; Tracy Becker from the Southwest Research Institute, and Chris Magri from the University of Maine.

That鈥檚聽what happened to 麻豆原创鈥檚 astrophysicist Gal Sarid, who studies comets, asteroids and planetary formation and earlier this year was part of a team that published a study focused on the comet 174P/Echeclus. It didn鈥檛 behave the way the team was expecting.

鈥淭his is another clue that Echeclus is a bizarre solar system object,鈥� said University of South Florida physics research Professor Maria Womack, who leads the team.

Comets streak across the sky and as they get closer to the sun look like bright fuzz balls with extended luminous trails in their wake. However, comets are actually bulky spheres of mixed ice and rock, many of them also rich in other frozen volatile compounds, such as carbon monoxide, carbon dioxide, hydrogen cyanide and methanol.

Comets heat up as they get closer to the sun, losing their icy layers by sublimation and producing emission jets of water vapor, other gases and dust expelled from the comet nucleus, Sarid said. Once they move away from the sun, they cool off again. But some comets start showing emission activity while still very far from the sun, where heating is low.

That鈥檚 what Sarid and Womack research as they study these kinds of distantly active comets. Womack and graduate student Kacper Wierzchos used the Arizona Radio Observatory Submillimeter telescope to observe Echeclus last year as it approached the sun. This work will be part of Wierzchos鈥� doctoral dissertation in applied physics at USF. Sarid provided theoretical expertise for interpreting the observational results.

Echeclus is part of the population of objects called centaurs, which have orbits around the sun at distances between that of Jupiter and Neptune. It is also part of a special group within the centaurs, which sometimes exhibit comet-like activity.聽 Previous research indicated that Echeclus might have been spewing carbon monoxide as its icy material changed phases.

The team found that the levels of carbon monoxide were nearly 40 times lower than typically expected from other comets at similar distances from the sun. This suggests that Echeclus and similar active Centaurs may be more fragile than other comets. Echeclus may have gone through a different physical process from most comets that caused it to lose a lot of its original carbon monoxide, or it may have had less of that substance to begin with.

Understanding the composition of comets and how they work will help researchers understand how our solar system was formed. It will also aid space explorers plan for their travels 鈥� things to avoid and perhaps hidden resources found within the nucleus of comets that may be useful on deep space missions.

鈥淭hese are minor bodies that we are studying, but they can provide major insights,鈥� Sarid said. 鈥淲e believe they are rich in organics and could provide important hints of how life originated.鈥�

Sarid is determined to solve the puzzle. This week he hosts a group of comet experts at 麻豆原创 to discuss the mysterious activity of Echeclus and other similar bodies. The idea for the workshop is to capitalize on the local expertise in observation, laboratory and theoretical work that is required to fully understand the mysteries of active comets at great distances from the sun. The inaugural Florida Distant Comets workshop was held a year ago at USF.

鈥淚 guess I鈥檝e always liked challenges,鈥� Sarid said from his office at the Florida Space Institute at 麻豆原创, where he spends his days trying to decipher the models and mathematical equations related to his work.

Sarid has a Ph.D. in geophysics and planetary Sciences from Tel Aviv University in Israel and completed postdoctoral work at the Institute for Astronomy and the NASA Astrobiology Institute in Hawaii, followed by a second postdoctoral research appointment at Harvard University. He was a part of a team that used the telescopes in Hawaii for several years chasing comets and asteroids for NASA observing campaigns and space missions before joining 麻豆原创 in 2014.

He teamed up with Womack in 2016 and on this most recent study provided theoretical expertise for interpreting the observational results.聽The National Science Foundation funds the project, under a grant awarded to USF, with Womack as the principal investigator and Sarid as a co-investigator.

They will continue to look at centaur-type comets and measure the level of their carbon monoxide emission and related activity.