NASA’s NEOWISE spacecraft helped break the secret of what lies on the surface of asteroids

The asteroid fighter spacecraft took thermal data from more than 100 space rocks close to Earth and revealed what happens with its surface regolith.

In December 2009, NASA launched the Wide Infrared Field Explorer (WISE) mission with the purpose of obtaining images of the entire sky in infrared light so that we can learn more about the stars, other galaxies and the celestial bodies in our own solar system.

After completing its main objective within two years, the WISE spacecraft remained inactive for another two years, when it awoke from its lethargy in 2013 and was given a new name and a new purpose.

Now called the Wide Field Infrared Survey Explorer of Near-Earth Objects (NEOWISE), the orbits of our planet's spacecraft to detect, identify and characterize near-Earth objects (the key is in the name ).

Armed with thermal sensors that allow it to make infrared observations, the NEOWISE spacecraft is actively seeking asteroids to gather data on its orbit, size, surface features and chemical composition. His mission has helped uncover the surface properties of more than 100 space rocks in the Asteroid Belt, NASA recently announced.

A new study published in the journal Icarus and available online at the arXiv server examined the NEOWISE archived and found a large amount of data that helped reveal what happens on the surface of many of the asteroids of the main belt.

The research, conducted by Josef Hanuš of the Astronomical Institute of Charles University in Prague, Czech Republic, used thermal observations of the NEOWISE spacecraft will perform a detailed "thermophysical" modeling of these asteroids and discover the properties of their surface regolith : fine grains of dust and broken rocks produced by thermal cracking and deposited on the surface of the asteroids.

Understanding the asteroids.
The temperature-sensitive look of #NEOWISE @WISE_Mission encourages the ability of @NASA to measure its size, chemical composition and surface characteristics.

– NASA JPL (@NASAJPL) June 2, 2018

"Thermophysical modeling is a mine of gold for asteroid researchers because it allows for a more comprehensive badysis of the nature of asteroids, "NASA officials said, noting that the NEOWISE thermal data helped build thermophysical models for three times as many asteroids as ever.

While reviewing the NEOWISE file, the researchers found infrared data for 122 asteroids they had previously modeled to see their shape and understand how they rotate. This helped to add thermal data to the 3D rotation and shape models of space rocks.

"Using archived data from the NEOWISE mission and our previously derived shape models, we were able to create highly detailed thermophysical models of 122 main belt asteroids," said Hanuš.

According to the main author of the study, NEOWISE thermal observations were fundamental to discover that asteroids have very little dust on their surface.

"We now have a better idea of ​​the properties of surface regolith and show that small asteroids, as well as fast spinning asteroids, have little or no dust covering their surfaces."

As explained by NASA, the fine grains of regolith have difficulty clinging to the surface of fast-moving space rocks, because the low gravity of the asteroids and the high rates of rotation prevent small particles from remaining attached to the surface .

Another reason for the lack of regolith in this type of asteroid could be linked to its small effects of thermal cracking. Since the sun's rays are distributed more rapidly through its surface of rapid rotation, these asteroids do not undergo large temperature changes and, therefore, are less prone to cracks and create fine grains of regolith.

Another thing that the new study unraveled was that the NEOWISE spacecraft did a fantastic job in collecting data on the size of asteroids.

Researchers reworked the calculations with more elaborate models and found that their results matched those of the NEOWISE team.

"The uncertainties were within 10 percent between the two sets of results," Hanuš said.


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