(ORDO NEWS) — An asteroid with three moons has been found for the first time in the solar system. The discovery was made using new image processing techniques and promises a revision of ideas about the evolution of asteroids.
Astronomers have proven that asteroids in the solar system can be much more diverse in structure than previously thought. For the first time, a quadruple asteroid, consisting of four separate satellite bodies, has been discovered. It turned out to be (130) Electra – an asteroid of the Main asteroid belt.
It was discovered back in 1873 by astronomer Christian Peters and named after Elektra, the heroine of Greek tragedies. Many years later, the asteroid again attracted the attention of astronomers, when in the 1990s it was possible to establish that Elektra has an irregular shape.
In 2003, it was discovered the first, and in 2004 – the second satellite, which attributed it to a rare type of triple asteroids.
Rare, but not unique – by that time, astronomers already knew over 150 asteroids with one and two moons gravitationally associated with them.
Now, advances in the latest methods of processing observations have made it possible to prove that it has not two, but at least three satellites, which makes Electra the first quadruple asteroid discovered in the solar system.
“A lot of moons can be found around large asteroids,” said Bin Yang, an astronomer at the European Southern Observatory who discovered Elektra’s second moon.
However, until recently, astronomers have not met asteroids consisting of four parts. Anthony Birdie, an astronomer from the National Research Institute of Thailand, managed to discover such an asteroid, and the same Elektra became the new record holder asteroid.
After analyzing images taken by the VLT (Very Large Telescope) telescope in Chile, Birdew and colleagues discovered a previously unnoticed third satellite of the asteroid between the orbits of the first two satellites.
“This is the first asteroid with three moons,” Birdew said. “We’re pretty confident about that, it’s amazing!”
The results of the study are published in the journal Astronomy & Astrophysics.
The discovery was made possible not thanks to new observations, but thanks to a new algorithm for processing old ones that Birded developed.
This algorithm allows, during processing, to reduce the illumination from the central bright body in the image by analyzing the so-called point spread function – in other words, taking into account the features of the light path inside the optical system of the telescope.
The application of this algorithm immediately helped to make out the three satellites of the asteroid. While the new satellite has not been given a name, the Minor Planet Center of the International Astronomical Union has instead given it the technical name S/2014 (130) 2.
The third satellite turned out to be a little more than a kilometer across – even smaller than the other two moons, whose dimensions are two and five kilometers. It revolves around Electra at a distance of 344 kilometers, despite the fact that the diameter of Electra itself is 200 km.
Yan, who was not involved in the study, said that she and other colleagues had been trying to find quadruple systems for some time, and she herself suspected that Elektra might have a third companion.
The discovery will yield “exciting results,” she said, though more observations are needed to definitively confirm the presence of the satellite.
According to Professor Alan Fitzsimmons from Queen’s University Belfast, most likely all three satellites are pieces of the main asteroid, which experienced a collision with another body in the distant past. “They all look like the same material,” he told the New York Times.
Further observations will help assess the stability of such systems. The fact is that the orbit of the third satellite does not lie in the plane of the first and second, which is “very strange,” notes Birdew. According to Yan, such a system is unstable and “inner satellites will eventually fall on Elektra.”
“This new discovery will inspire modelers to study asteroid collisions and try to put a limit on how many satellites they can form. And how many satellites can the system hold?” Yan added.
Scientists hope that in the future, asteroids with a large number of satellites will be easily discovered using large, new-generation ground-based telescopes, such as the Extremely Large Telescope in Chile.
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