Unknown ‘mini-moon’ in outer solar system is one of the smallest ever discovered: ScienceAlert
Astronomers may have detected a previously unknown “mini-moon” in the solar system: a rocky object orbiting a small asteroid near Jupiter.
If the rocky satellite, which is just a little wider than the width of Manhattan, turns out to be a real moon, it would be one of the smallest moons ever spotted.
The tiny satellite was discovered by scientists working at NASA Mission Luciawho sends a space probe to study some of the Trojans asteroidstwo massive groups of space rocks which are located on either side of Jupiter in its orbit around the Sun.
The Lucy probe was launched on October 16, 2021 and will arrive at the Trojan asteroids in late 2027, after making a quick stop in the asteroid belt between March and Jupiter.
Until then, scientists on the Lucy mission are trying to learn more about some of these mysterious rocks to help identify where the probe can be most useful.
On March 27, the smallest of Lucy’s Trojan targets, known as Polymele, passed in front of a distant star, allowing mission scientists to precisely measure the size of the space rock by observing the amount of light from the star that the asteroid blocked in passing.
However, the team also observed an unexpected small subsequent blip as a second asteroid followed Polymele’s wake.
After reviewing the data, the team concluded that the second blip “must be a satellite,” lead researcher Marc Buie, an astronomer at the Southwest Research Institute in Boulder, Colorado, said in a NASA report. statement.
The newly discovered satellite has a diameter of about 3 miles (5 kilometers) and is separated from Polymele 17 miles wide (27 km) by a distance of about 125 miles (201 km). At the time of the sighting, Polymele was approximately 480 million miles (772 million km) from Earth.
“These distances are roughly equivalent to finding a quarter on a sidewalk in Los Angeles while trying to spot it from a skyscraper in Manhattan,” NASA officials wrote in the release.
The term “moon“can refer to any natural solid body that orbits a planet, dwarf planet, or asteroid. Over 200 moons have been recognized in the Solar system (not including asteroid moons), but the actual number is likely much higher, according to Nasa.
Researchers have only been able to make fleeting observations of Polymele’s satellite, so its orbital path is highly uncertain. As a result, the space rock cannot yet be officially designated as a moon or properly named.
But the researchers are confident that when the Lucy probe arrives at Polymele, the spacecraft will be able to collect enough data to designate it as a real moon.
This is not the first time that scientists from the Lucy mission have spotted a satellite tracking a Trojan asteroid.
In 2021, the team detected a 0.6-mile-wide (1 km) satellite orbiting Eurybates, which will be Lucy’s first Trojan target, after analyzing data collected by the Hubble Space Telescope from NASA, according to the Live Science sister site. Space.com. On this occasion, the researchers determined the orbital trajectory of the moon and officially named it Queta.