After its brief visit, 2001 FO32 will continue its solitary journey and will not come as close to Earth again until 2052, when it will pass about seven lunar distances, or 1.75 million miles (2.8 million kilometers).
Asteroid 2001 FO32 was discovered in March 2001 by the Lincoln Near-Earth Asteroid Research (LINEAR) program in Socorro, New Mexico, and had been estimated, based on optical measurements, to be approximately 3,000 feet (1 kilometer) wide. In more recent NEOWISE follow-up observations, 2001 FO32 appears to be faint when viewed at infrared wavelengths, suggesting that the object is likely less than 1 kilometer in diameter. Analysis by the NEOWISE team shows that it is between 1,300 and 2,230 feet (440 and 680 meters) wide.
Even if it is on the smaller end of the scale, 2001 FO32 will still be the largest asteroid to pass this close to our planet in 2021. The last remarkably large asteroid approach was that of 1998 OR2 on April 29, 2020. While Since 2001 FO32 is somewhat smaller than 1998 OR2, it will be three times closer to Earth.
The March 21 encounter will provide an opportunity for astronomers to gain a more precise understanding of the asteroid’s size and albedo (that is, how bright or reflective its surface is), and a rough idea of its composition.
This will be accomplished, in part, with the use of NASA’s Infrared Telescope Facility (IRTF), a 3.2-meter (10.5-foot) telescope on Hawaii’s Mauna Kea that will observe the asteroid in the days leading up to it. to the close approach with his workhorse. infrared spectrograph, SpeX. “We’re trying to do geology with a telescope,” said Vishnu Reddy, an 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 minerals on the asteroid’s surface. “We are going to use the IRTF to get the infrared spectrum to see its chemical composition,” Reddy explained. “Once we know that, we can make comparisons with meteorites on Earth to find out what minerals 2001 FO32 contains.”
For example, if 2001 FO32 were identified as rich in iron, that would mean that it is denser and therefore more massive than a rocky asteroid of similar size; Observations showing a surface with a low albedo (meaning it’s dark) may indicate that the asteroid contains a large amount of carbon, suggesting it could be the nucleus of a long-dead comet.
A closer look
In addition, radar observations can be made by the Deep Space Network (DSN) to obtain a detailed view of the asteroid. An operation of NASA’s Space Navigation and Communications (SCaN) program, the DSN comprises three ground stations: one in California (Goldstone), one in Spain (Madrid) and one in Australia (Canberra). Your satellite dishes can be used to bounce 2001 FO32 radio signals so that other radio antennas can receive them. These radar observations can provide additional information about the asteroid’s orbit, provide a better estimate of its dimensions and rotational speed, and help glimpse surface features (such as large rocks or craters). They could even reveal any small satellites that may be towed.
“Observations dating back 20 years revealed that about 15% of near-Earth asteroids comparable in size to FO32 from 2001 have a small moon,” said Lance Benner, lead scientist at JPL. “Currently little is known about this object, so the very close encounter provides a rare opportunity to learn a lot about this asteroid.”
More than 95% of near-Earth asteroids the size of 2001 FO32 or larger have been discovered, tracked, and cataloged. None of the large asteroids in the catalog have any chance of impacting Earth over the next century, and it is extremely unlikely that any of the undiscovered asteroids of this size will be able to impact Earth either. Still, efforts continue to discover all the asteroids that could pose an impact hazard. The more information that can be gathered about these objects, the better mission designers can prepare to deflect them if one threatens Earth in the future.
Meanwhile, amateur astronomers can gather their own information on 2001 FO32. “The asteroid will be brighter as it moves through the southern skies,” said JPL’s Chodas. “Amateur astronomers in the southern hemisphere and in low northern latitudes should be able to see this asteroid using moderately sized telescopes with apertures of at least 8 inches in the nights before the closest approach, but they will probably need star charts to find it. “
JPL hosts CNEOS for NASA’s Near-Earth Object Observation Program at NASA’s Planetary Defense Coordination Office. The University of Hawaii manages the IRTF under contract with NASA. The SpeX instrument was built at the University of Hawaii.
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