Earth just gained a new mini-moon
How was it found: The asteroid, called 2020 CD3 (also known as C26FED2), was discovered by the Catalina Sky Survey at the University of Arizona on February 15. The two researchers responsible for the discovery held off on announcing their findings while they confirmed exactly what 2020 CD3 was and what its orbit looked like. Its small size and peculiar orbit helped hide it well from astronomers.
Mini moons are formally known as Temporary Captured Orbiters (TCO)—objects that are currently looping the planet, but will eventually shove off and resume their trip around the sun. CSS previously found a TCO that stumbled into Earth’s orbit in 2006, before exiting the following year.
Earth might have a tiny new moon. On 19 February, astronomers at the Catalina Sky Survey in Arizona spotted a dim object moving quickly across the sky. Over the next few days, researchers at six more observatories around the world watched the object, designated 2020 CD3, and calculated its orbit, confirming that it has been gravitationally bound to Earth for about three years.
An announcement posted by the Minor Planet Center, which monitors small bodies in space, states that “no link to a known artificial object has been found”, implying that it is most likely an asteroid caught by Earth’s gravity as it passed by.
This is just the second asteroid known to have been captured by our planet as a mini-moon – the first, 2006 RH120, hung around between September 2006 and June 2007 before escaping.
Our new moon is probably between 1.9 and 3.5 metres across, or roughly the size of a car, making it no match for Earth’s primary moon. It circles our planet about once every 47 days on a wide, oval-shaped orbit that mostly swoops far outside the larger moon’s path.
The tiny asteroid, dubbed 2020 CD3, was spotted by astronomers in Tucson, Arizona, on Feb. 15.
“BIG NEWS,” Kacper Wierzchos, a researcher with the Catalina Sky Survey at the University of Arizona’s Lunar and Planetary Lab, tweeted Tuesday. “Earth has a new temporarily captured object/Possible mini-moon called 2020 CD3. On the night of Feb. 15, my Catalina Sky Survey teammate Teddy Pruyne and I found a 20th magnitude object.”
Wierzchos said that the object measures about 6 feet to 11 feet across and that its orbit suggests that it entered Earth’s orbit around three years ago.
In its official designation, the IAU said observations “indicate that this object is temporarily bound to Earth.” The organization added: “No evidence of perturbations due to solar radiation pressure is seen, and no link to a known artificial object has been found. Further observations and dynamical studies are strongly encouraged.”
The last asteroid to get caught in Earth’s orbit was 2006 RH120. The space rock, which orbits the sun and passes close to Earth every few decades, was captured by the planet’s gravity in June 2006 and stayed until around September 2007, before it swung back out into the solar system.
We could have a new space neighbor, at least for a while. Astronomers at the NASA-funded Catalina Sky Survey reckon they’ve spotted an asteroid that’s caught in Earth’s gravity.
“Earth has a new temporarily captured object/Possible mini-moon called 2020 CD3. On the night of Feb. 15, my Catalina Sky Survey teammate Teddy Pruyne and I found a 20th magnitude object,” Kacper Wierzchos tweeted Tuesday.