Possibly the first truly pristine comet ever observed

2I/Borisov passed near the Sun. The colors in these streaks give the image some disco flair and are the result of combining observations in different wavelength bands, highlighted by the various colors in this composite image. Credit:ESO/O. Hainaut
This image was taken with the FORS2 instrument on ESO’s Very Large Telescope in late 2019, when comet 2I/Borisov passed near the Sun. Since the comet was traveling at breakneck speed, around 175 000 kilometers per hour, the background stars appeared as streaks of light as the telescope followed the comet’s trajectory. The colors in these streaks give the image some disco flair and are the result of combining observations in different wavelength bands, highlighted by the various colors in this composite image. Credit:ESO/O. Hainaut

MARCH 30 — New observations with the European Southern Observatory’s Very Large Telescope (ESO’s VLT) indicate that the rogue comet 2I/Borisov, which is only the second and most recently detected interstellar visitor to our Solar System, is one of the most pristine ever observed. Astronomers suspect that the comet most likely never passed close to a star, making it an undisturbed relic of the cloud of gas and dust it formed from.

Comet 2I/Borisov was discovered by amateur astronomer Gennady Borisov in August 2019 and was confirmed to have come from beyond the Solar System a few weeks later. “2I/Borisov could represent the first truly pristine comet ever observed,” says Stefano Bagnulo of the Armagh Observatory and Planetarium, Northern Ireland, UK, who led the new study published today in Nature Communications. The team believes that the comet had never passed close to any star before it flew by the Sun in 2019.

Bagnulo and his colleagues used the FORS2 instrument on ESO’s VLT, located in northern Chile, to study 2I/Borisov in detail using a technique called polarimetry. Since this technique is regularly used to study comets and other small bodies of our Solar System, this allowed the team to compare the interstellar visitor with our local comets.

The team found that 2I/Borisov has polarimetric properties distinct from those of Solar System comets, with the exception of Hale–Bopp. Comet Hale–Bopp received much public interest in the late 1990s as a result of being easily visible to the naked eye, and also because it was one of the most pristine comets astronomers had ever seen. Prior to its most recent passage, Hale–Bopp is thought to have passed by our Sun only once and had therefore barely been affected by solar wind and radiation. This means it was pristine, having a composition very similar to that of the cloud of gas and dust it — and the rest of the Solar System — formed from some 4.5 billion years ago.

By analyzing the polarization together with the color of the comet to gather clues on its composition, the team concluded that 2I/Borisov is in fact even more pristine than Hale–Bopp. This means it carries untarnished signatures of the cloud of gas and dust it formed from.

“The fact that the two comets are remarkably similar suggests that the environment in which 2I/Borisov originated is not so different in composition from the environment in the early Solar System,” says Alberto Cellino, a co-author of the study, from the Astrophysical Observatory of Torino, National Institute for Astrophysics (INAF), Italy.

Olivier Hainaut, an astronomer at ESO in Germany who studies comets and other near-Earth objects but was not involved in this new study, agrees. “The main result — that 2I/Borisov is not like any other comet except Hale–Bopp — is very strong,” he says, adding that “it is very plausible they formed in very similar conditions.”

“The arrival of 2I/Borisov from interstellar space represented the first opportunity to study the composition of a comet from another planetary system and check if the material that comes from this comet is somehow different from our native variety,” explains Ludmilla Kolokolova, of the University of Maryland in the US, who was involved in the Nature Communications research. 

Bagnulo hopes astronomers will have another, even better, opportunity to study a rogue comet in detail before the end of the decade. “ESA is planning to launch Comet Interceptor in 2029, which will have the capability of reaching another visiting interstellar object, if one on a suitable trajectory is discovered,” he says, referring to an upcoming mission by the European Space Agency.

March 8 Membership Meeting, OSIRIS-REx to Bennu!

This artist's rendering shows OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid’s surface. Image Credit: NASA/Goddard/University of Arizona
This artist’s rendering shows OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid’s surface. Image Credit: NASA/Goddard/University of Arizona

The February Membership Meeting of the Cuyahoga Astronomical Association (CAA) will take place Monday, February 8, from 7:30 to 9:00 p.m. via the Zoom online meeting service.

The evening’s speaker will be Jeff Woytach, retired NASA Scientist whose talk is entitled, “OSIRIS-REx: Mission to Bennu!” OSIRIS-REx is a U.S. mission to return samples from the Near Earth Asteroid Bennu to Earth, and to measure theoretical effects on the asteroid to see how its orbit is perturbed. Bennu is an Earth-crossing asteroid that has the potential to impact our planet. The presentation will talk about the accomplishments of the mission, as well as other sample return missions that have been accomplished or are on the books for the future.

Woytach, originally from Scranton, Pennsylvania, earned a Bachelor of Science in Aerospace Engineering from the Pennsylvania State University in May 1983. He joined the staff of the National Aeronautics and Space Administration’s John H. Glenn Research Center (GRC) in June 1983.

Woytach has worked on space missions launched on the Space Shuttle and the Atlas/Centaur launch vehicle, and on flight hardware for the International Space Station. He is currently the Systems Engineer for the Fission Surface Power System, which will place a nuclear fission reactor on the lunar surface. Mr. Woytach also provides systems engineering support to the Psyche mission.

Led by the Jet Propulsion Laboratory (JPL), Psyche will visit an asteroid believed to be composed entirely of metal. In addition, Jeff is the systems engineer for a small spacecraft being developed to perform ocean research for the National Oceanic Partnership Program. He is also the lead for two university student design competitions sponsored by NASA, involving teams from five U.S. universities In his spare time, Mr. Woytach enjoys space exploration history, collecting space exploration memorabilia, astronomy, and “Star Trek”. He is also the founder of the “Glenn Band,” a concert band comprised of NASA Glenn employees and retirees, their family members and students from the North Olmsted School District. Mr. Woytach and his family are residents of North Ridgeville, Ohio.

Attendees may join the Zoom meeting beginning at 7:20 p.m. the nights of CAA scheduled meetings and meetings begin at 7:30.

The evening will begin with introductions and the featured speaker followed by the monthly membership business meeting, typically concluding at about 9 p.m.. Guest attendees are welcome.

To attend:

You can either “Phone in” or watch and participate via “Zoom Video”.

Phone In:  Just dial:  1-312-626-6799  (Chicago number)

You will be required to enter our meeting number:  954 8268 6049

Zoom Video with video and audio, on your web browser. (No camera required)

Or download the desktop application from: https://zoom.us/download#client_4meeting

Ride the rover to the surface of Mars

February 22, 2021 — New video from NASA’s Mars 2020 Perseverance rover chronicles major milestones during the final minutes of its entry, descent, and landing (EDL) on the Red Planet on Feb. 18 as the spacecraft plummeted, parachuted, and rocketed toward the surface of Mars. A microphone on the rover also has provided the first audio recording of sounds from Mars.

From the moment of parachute inflation, the camera system covers the entirety of the descent process, showing some of the rover’s intense ride to Mars’ Jezero Crater. The footage from high-definition cameras aboard the spacecraft starts 7 miles (11 kilometers) above the surface, showing the supersonic deployment of the most massive parachute ever sent to another world, and ends with the rover’s touchdown in the crater.

Perseverance lowered safely to Martian surface

This high-resolution still image is part of a video taken by several cameras as NASA’s Perseverance rover touched down on Mars on Feb. 18, 2021. A camera aboard the descent stage captured this shot. A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust). Subsequent NASA missions, in cooperation with ESA (the European Space Agency), would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis. The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance and Curiosity rovers.
Credits: NASA/JPL-Caltech