According to a paper published in the latest issue of the Astrophysical Journal Newsletter, Thai astronomers have discovered that an asteroid discovered in the 19th century has three smaller companion moons, the first quadrangle system ever detected. Of the 1.1 million asteroids that have been discovered, more than 150 are known to have at least one satellite.
A team of astronomers led by Anthony Berdeu of Thailand's National Astronomical Institute reportedly made the discovery.
Thai astronomers discovered the quadruple system using data from the European Southern Observatory.
The asteroid named 130 Elektra, a 160-mile-wide space rock in the small star belt between Jupiter and Mars, was first discovered in 1873. However, it was not until 130 years later that its first satellite was discovered, and it was not until 2014 that the second satellite was discovered.
They are so difficult to detect because asteroids are only small and have dim light, so any smaller orbiter is relatively dim and is likely to be greatly overshadowed by its parent asteroid.
The Artist depicts the Elektra Quadruple System.
Elektra's three satellites are named S/2003(130)1, S/2014(130)1 and S/2014(130)2.
The first satellite, with a diameter of 3.7 miles (6 km), orbited Elektra at an average distance of about 807 miles (1300 km), while the second was only 1.24 miles (2 km) in diameter and had an average orbital distance of 310 miles (500 km).
The newly discovered satellite is smaller and closer, 1 mile (1.6 km) wide and has an average orbital distance of about 211 miles (340 km).
S/2014(130)2 orbits its parent star every 16.3 hours, 15,000 times dimmer than Elektra.
Schematic diagram of the position relationship of the Elektra quadruple system.
The researchers say the discovery of the first quadruple asteroid system opens the way to understanding the formation mechanisms of these moons "slightly."
They hope the results of this research may lead to the discovery of other faint, hard-to-see asteroid moons in the future.
Text/Nandu reporter Chen Lin