It turns out that the asteroid has at least three (!)

It makes the Electra the first quadrupedal asteroid system discovered to date.

Exactly between the orbits of Mars and Jupiter we find the so-called asteroid belt. This belt is full of unusual space rocks, which may represent the remnants of our early solar system. One of these interesting asteroids is Electra. And now researchers have discovered that this part of space is home not to one or two, but even three moons.

Electra satellites
It was already known that two moons orbited Electra. But a team of astronomers has now discovered another satellite orbiting the asteroid.

The Electra system and its three moons. Shown here are the two moons already known by their orange and green bands. The blue orbit relates to the newly discovered moon. Photo: ESO/Berdeu et al., Yang et al.

Electra’s new third moon was initially named S/2014 (130) 2 and is slightly closer to Electra than the other two moons. For example, laps swim just under 350 kilometers and complete a circuit around the mother’s body every 16.3 hours. The Moon also has a somewhat surprising tilted orbit compared to its sisters and the axis of rotation of the Electra itself.

Quad asteroid system
The discovery of a third moon is very special. Because it is the first time that astronomers have encountered an asteroid that contains at least three moons. It makes the Electra the first quadrupedal asteroid system found to date.

Discovery
The research team tracked the new Electra satellite thanks to observations made with the SPHERE instrument on the European Southern Observatory (ESO) Very Large Telescope in Chile (see box). This tool is a powerful tool that astronomers usually use to search for new planets.

In addition, research leader Anthony Purdue has developed a new algorithm that will allow him to process data better than SPHERE. SPHERE’s sensitivity, combined with advanced data processing techniques, allowed the team to reveal Elektra’s newest satellite.

evades
What makes this discovery particularly noteworthy is that the researchers used the same data set with which astronomers previously discovered Electra’s second moon. The fact that the third moon eluded the research team at that time can easily be explained. For example, it cannot be detected using normal data processing techniques. So Berdeu’s new algorithm is a big step forward. Because the algorithm can increase the capacity of the tools. This then allowed the team to pick up even the faint signal from the Electra’s third moon.

So the newly developed Berdeu algorithm has a lot of potential. Because if this had not been applied to the Elektra data set, we would not know that there is a third moon around the asteroid today. This means that there may still be many new celestial bodies waiting to be discovered in the mountains of archival data collected by the SPHERE instrument.