Opened last year the first Trojan asteroid of Jupiter 2019 LD2 turned out to be a comet. Install it helped the analysis of its trajectories for all time of observations: it is confirmed that the body is not in orbital resonance 1:1 with planet, as expected for a Trojan. The comet was named P/2019 LD2 (ATLAS), the circular published on the website of the minor planet Center.
10 Jun 2019 system ground-based telescopes ATLAS (Asteroid Terrestrial-impact Last Alert System) detected a dim object near the orbit of Jupiter. The body, the designation of 2019 LD2, identified as the Trojan asteroid from the vicinity of the Lagrange point L4 in the system Sun–Jupiter. Analysis of images showed that this object exhibits cometary activity: this was confirmed by observations made on 11 and 13 June 2019 with the help of telescopes of the Las Cumbres Observatory. In July 2019 and April 2020 system ATLAS again watched 2019 LD2 and confirmed that he has a dim tail of gas and dust: it shows a continuous activity of the asteroid during the year.
Such behavior is considered unusual for the Trojan asteroids of Jupiter, as it is believed that they were captured by the gravity of a giant a few billion years ago, and during this time any surface layers of ice had sublimed. Scientists, therefore, suggested that 2019 LD2 had been seized by Jupiter not so long ago, or some process (collision with another body or landslide) revealed layers of ice that lies beneath the surface of the asteroid.
Recent analysis of the trajectory of the asteroid for the time of the observations showed that it is not in a stable orbital resonance 1:1 with planet in 2017 was close to her: it’s not like the behavior of Trojans. The asteroid, therefore, have been reclassified as comets of the Jupiter family and received the designation P/2019 LD2 (ATLAS). Estimating the size of the comet’s nucleus is estimated at 4.8 miles, and one revolution around the Sun, it makes for a little more than 12 years.
The study of the Trojan asteroids of Jupiter is the main task of the new interplanetary station “Lucy”, the start of which is scheduled for October 2021. Recently the space telescope “Hubble” has confirmedthat the asteroid of Eurobat, which is one of the goals of the station, has a small satellite which makes it a very interesting object for research.