The largest paper ever published on radar observations of near-Earth asteroids has been released, compiling years’ worth of data from the Arecibo Observatory in Puerto Rico.
Using delay-Doppler radar observations collected from the observatory between December 2017 and December 2019, the study includes 191 asteroids’ radar cross sections and Doppler-frequency broadening. This data can be used as clues to asteroids’ spin periods and sizes, as well as polarization information for 110 of them, which could help to understand the surface and subsurface properties. Thirty-seven asteroids were presented in greater detail with more refined size evaluation, preliminary shape evaluation, information about how reflective they are in radar, and if the radar observations match with the visual and near-infrared observations.
The work was published recently in the Planetary Sciences Journal.
As one of the only papers of its kind that includes a large number of asteroid targets, the study serves as a “treasure trove of data” for planetary scientists given that most existing literature only focuses on one object at a time, says Anne Virkki, the study’s lead author and a researcher with the Department of Physics at the University of Helsinki in Finland.
The study’s ample amount of asteroid data is important for many reasons, the researchers say.
Although Arecibo’s planetary radar group focuses on supporting NASA’s planetary defense program, the study’s wealth of information has economic benefits as well, supplying asteroid mining companies with data on metal-rich and ice-rich near-Earth asteroids containing resources of interest.
The diversity of asteroid data in general also clues other scientists in on the formation and evolution of the solar system.
Radar is the best ground-based tool for near-Earth asteroid characterization, says Flaviane Venditti, head of Arecibo’s Planetary Radar Science Group and study co-author.
“The amount of valuable data collected is unique, and these results could not have been achieved with any other existing facility,” Venditti says.
Through the study, scientists found two near-Earth asteroids with abnormally high radar albedos, or reflectivity in radar, suggesting that they could be metal-rich. The possibility of two more is significant; few metal-rich NEAs have been found so far.
Another high radar albedos near-Earth asteroid, rare equal-mass binary 2017 YE5, was suggested to have ice below its surface instead of metal richness due to its low bulk density. Classified in the study as a D-type NEA, 2017 YE5 is potentially the first of its kind observed using radar.
More classifications were made with scientists listing five possible enstatite-rich, or E-type, asteroids that had not been identified as such previously, using polarization information from radar.
Accompanying the data were numerous 7.5m resolution asteroid images, a feature uncommon in existing literature. No other ground-based instrument than radar can take images at a resolution finer than 10m of any celestial objects further than the moon, and until the telescope’s collapse in 2020, the Arecibo radar was the most powerful and sensitive planetary radar in the world.
Future Research
Though plentiful in its data, the study leaves doors open for further research.
“This paper is like a teaser for a full movie,” Virkki says.
Venditti says the data from the research shows how rich the information obtained with radar is.
“In fact, there’s still a lot of high-quality data to be analyzed in detail, which could even support planning future spacecraft missions to small bodies,” Venditti says.
Funding
Funding for the research was provided through NASA’s Near-Earth Object Observations program. The University of Central Florida manages the Arecibo Observatory for the U.S. National Science Foundation under a cooperative agreement.
Study title: Arecibo Planetary Radar Observations of Near-Earth Asteroids: 2017 December–2019 December
Researchers’ Credentials
Virkki received her doctorate in astronomy from the University of Helsinki in 2016. She currently works at the University of Helsinki in the planetary science research group. Virkki joined the Arecibo Observatory in April 2016 and the University of Central Florida in April 2018. She served as head of Arecibo’s Planetary Radar Science Group from 2018 to 2021.
Venditti received her doctorate in space engineering at the National Institute for Space Research in Brazil in 2013. She joined Arecibo Observatory in 2017 and has served as head of its Planetary Radar Science Group since 2021.
Other Arecibo planetary radar members who contributed to the study include observatory scientists Sean Marshall and Maxime Devogèle, and data analysts Luisa Zambrano-Marín and Anna McGilvray.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
