After its brief visit, the FO32 will continue its solitary journey in 2001, not reaching Earth again until 2052, when it will pass at about seven lunar distances, or 1.75 million miles (2.8 million kilometers).
Astronomical Geology
Asteroid 2001 FO32 was discovered in March 2001 by the Lincoln Near-Earth Asteroid Research (LINEAR) program in Socorro, New Mexico, and was estimated to be about 3,000 feet (1 kilometer) wide based on optical measurements. In more recent follow-up observations by NEOWISE, FO32 from 2001 appears to be faint when observed in infrared wavelengths, suggesting that the object is likely less than 1 kilometer in diameter. Analysis by the NEOWISE team shows that it is between 440 and 680 meters wide.
Even if it is at the smaller end of the scale, FO32 will still be the largest asteroid this close to our planet in 2001 in 2001. The last notably large asteroid up close was that of 1998 OR2 on April 29, 2020. While 2001 FO32 is slightly smaller than 1998 OR2, it will be three times closer to Earth.
The March 21 encounter provides astronomers with an opportunity to gain a better understanding of the asteroid’s size and albedo (i.e., how bright or reflective its surface is), and to get a rough idea of its composition .
This will be accomplished in part using NASA’s Infrared Telescope Facility (IRTF), a 3.2-meter (10.5-foot) telescope atop Hawaii’s Mauna Kea that will observe the asteroid at close range in the days leading up to the approach. using his workhorse. infrared spectrograph, SpeX. “We’re trying to do geology with a telescope,” said Vishnu Reddy, associate professor at the Lunar and Planetary Laboratory at the University of Arizona in Tucson.
When sunlight hits the surface of an asteroid, minerals in the rock absorb some wavelengths while reflecting others. By studying the spectrum of light reflected from the surface, astronomers can measure the chemical “fingerprints” of the minerals on the asteroid’s surface. “We’re going to use the IRTF to show the infrared spectrum its chemical composition,” explained Reddy. “Once we know that, we can make comparisons with Earth’s meteorites to find out which minerals 2001 contains FO32.”
For example, if FO32 from 2001 were identified as iron rich, it would mean that it is denser and therefore more massive than a stony asteroid of similar size; Observations showing a surface with a layer of albedo (meaning it is dark) may indicate that the asteroid is high in carbon, suggesting it may be the nucleus of a long-dead comet.
A closer look
In addition, radar observations can be performed by the Deep Space Network (DSN) to get a detailed view of the asteroid. The DSN, an operation of NASA’s Space Communications and Navigation (SCaN) program, includes three ground stations: one in California (Goldstone), one in Spain (Madrid), and one in Australia (Canberra). Their satellite dishes can be used to bounce 2001 FO32 radio signals so that other radio antennas can receive them. Such radar observations can provide additional insight into the asteroid’s orbit, better estimate its size and rotational speed, and help glimpse surface features (such as large boulders or craters). They can even reveal small satellites that may be in tow.
“Observations going back 20 years showed that about 15% of near-Earth asteroids comparable in size to 2001’s FO32 have a small moon,” said Lance Benner, JPL chief scientist. “Little is currently known about this object, so the very close encounter provides an excellent opportunity to learn a lot about this asteroid.”
More than 95% of near-Earth asteroids the size of FO32 2001 or greater have been discovered, tracked, and cataloged. None of the large asteroids in the catalog have any chance of impacting Earth in the next century, and it is extremely unlikely that any of the remaining undiscovered asteroids of this size could hit Earth as well. Still, efforts to discover all asteroids that could pose an impact hazard continue. The more information that can be gathered about these objects, the better mission designers can prepare to deflect them should they threaten Earth in the future.
Meanwhile, amateur astronomers can gather information for themselves about FO32 from 2001. “The asteroid will be brightest as it moves through the southern sky,” said JPL’s Chodas. “Amateur astronomers in the southern hemisphere and low northern latitudes should be able to see this asteroid using medium-sized telescopes with apertures of at least 20 cm in the nights leading up to the closest approach, but they will likely need star charts to find it. “
JPL hosts CNEOS for NASA’s Near-Earth Object Observations Program in NASA’s Planetary Defense Coordination Office. The University of Hawaii manages IRTF under contract with NASA. The SpeX instrument was built at the University of Hawaii.
More information about CNEOS, asteroids and near-terrestrial objects can be found at:
https://cneos.jpl.nasa.gov
For more information about NASA’s Planetary Defense Coordination Office, please visit:
https://www.nasa.gov/planetarydefense
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