Earth's orbit has a 2nd trojan asteroid, confirms latest study; will linger for 4,000 yrs

What was previously speculated to be just the second known trojan asteroid in the Earth’s orbit has been confirmed by astronomers following a new research. Named 2020 XL5, the space rock was stumbled upon in 2020 and was discovered travelling ahead of our planet but in the same solar orbit. With this confirmation, astronomers have added another trojan asteroid to the list that previously only consisted of 2010 TK7.

Trojan asteroids basically are objects that park themselves at gravitationally stable locations in space, called Lagrange points and share the orbit belonging to a particular planet. According to the astronomers, the 2020 XL5 is located at the fourth Lagrange point, approximately 60 degrees ahead of Earth and will stay there for the next 4,000 years. 

Features of the asteroid

In the new study, co-authored by the University of Barcelona's Toni Santana-Ros, the experts also specified the features of the asteroid, which is even more impressive than its counterpart. The newly found trojan asteroid is three times the size of 2010 TK7 and measures approximately 1.18 kilometres in width. A dark and carbon-rich object, 2020 XL5 is a C-complex type asteroid and became a trojan just 600 years ago, the experts noted. 

The asteroid was discovered on December 12, 2020, using the Pan-STARRS1 survey telescope in Hawai‘i. however, the insufficient data delayed its confirmation. The astronomers then conducted follow-up observations using the Chile-based Southern Astrophysical Research (SOAR) Telescope, the Arizona-based Lowell Discovery Telescope and the European Space Agency’s Optical Ground Station. 

"In order to improve the knowledge of its orbit, we performed follow-up observations in February and March 2021, which allowed us to calculate with great accuracy the orbit of the object. In turn, this allowed us to find ancillary data of the object in the data archive", Santana-Ros told Gizmodo. Following this discovery, astronomers now believe that there might be many other trojan asteroids in the Lagrange points which are yet to be discovered. Besides, the newly found object can also serve as a target for flyby missions in the future. Jupiter is also known to have a huge number of trojan asteroids in its orbit, something which prompted NASA to launch the Lucy mission last year. 

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