(ORDO NEWS) — Scientists have published the largest paper on radar observations of near-Earth asteroids, which collected many years of data from the Arecibo Observatory in Puerto Rico.
Based on Doppler-lag radar observations collected by the observatory between December 2017 and December 2019, the study describes the radar cross sections and Doppler broadening of 191 asteroids.
These data can be used to study the rotation periods and sizes of these asteroids, as well as information on the polarization of 110 of them, which can help in understanding the properties of their surface and interior.
Thirty-seven asteroids were examined in more detail, with more accurate size estimates, preliminary shape estimates, information about their reflective features on the radar, and whether radar observations match visual and near-infrared observations.
The researchers argue that such a large amount of data on asteroids is important for many reasons.
For example, the article includes characteristics of several potentially hazardous asteroids. Observations from Arecibo have already contributed to past planetary defense efforts, including the recent DART mission.
While the Arecibo Planetary Radar Group is focused on supporting NASA‘s planetary defense program, the wealth of information generated by the study also has economic benefits, providing asteroid mining companies with data on metal- and ice-rich near-Earth asteroids containing resources of interest. .
The diversity of asteroid data also helps other scientists understand the formation and evolution of the solar system.
Radar is the best ground-based tool for characterizing near-Earth asteroids, says Flavian Venditti, head of the Planetary Radar Science Group at Arecibo and co-author of the study.
“The amount of valuable data collected is unique, and such results would not be possible with any other existing equipment,” says Venditti.
Although the telescope collapsed in 2020, scientists continue to analyze the data collected from it.
Additional findings
In the course of the study, scientists found two near-Earth asteroids with anomalously high radar albedo (reflectivity in the radar), suggesting that they may be rich in metals. It is very important; so far, only a few metal-rich NEAs (Near-Earth Asteroids) have been discovered.
Another near-Earth asteroid with a high radar albedo, 2017 YE5, a rare equal-mass binary, has been suggested to have ice rather than metal below the surface due to its low bulk density. 2017 YE5, classified as a D-type NEA in the study, is potentially the first of its kind observed by radar.
Additional classifications have also been created. Scientists have listed five possible enstatite-rich or E-type asteroids that have never been identified before. The polarization information was obtained from the radar.
The data was accompanied by numerous images of asteroids at a resolution of 7.5 m, which is rare in existing studies.
No ground-based instrument other than radar can capture images below 10m resolution of any celestial objects farther than the Moon, and until the telescope collapsed in 2020, Arecibo radar was the most powerful and sensitive planetary radar in the world.
Future research
Despite the abundance of data, the study leaves room for further research.
“This article is like a teaser for a feature film,” Virkki says.
Venditti says the data from the study shows just how rich the information obtained from the radar is.
“In fact, there is still a lot of high-quality data that needs to be analyzed in detail, which could even help plan future spacecraft missions to small bodies,” says Venditti.
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