With ESA probe "Gaia":

Possibly hundreds of double asteroids discovered

Thanks to the "Gaia" space probe (image), astronomers have found hundreds of new possible double asteroids.

(Bild: ESA/ATG medialab, ESA/Gaia/DPAC, A. Moitinho (CC BY-SA 3.0 IGO))

Thanks to the "Gaia" space probe, astronomers have found hundreds of new possible double asteroids (also known as asteroid moons). According to the European Space Agency ESA, 352 new double asteroids could have been discovered with the help of the telescope in space.

"Double asteroids are difficult to find because they are usually small and far away from us," the ESA quotes the author of the study, Luana Liberato from the Observatoire de la Côte d'Azur. It is assumed that almost every sixth asteroid has a companion. However, of the approximately one billion asteroids, only 500 such double asteroids have been discovered so far.

What is a double asteroid?

A double planetoid or double asteroid is a system of two gravitationally bound asteroids that both move around a common center of gravity.

If one of the celestial bodies is significantly larger than the other, it is usually referred to as the moon or satellite of the asteroid or also as an asteroid moon or planetoid moon. Such a system is comparable to the Earth-moon system or binary stars.

"Gaia" mission on a great quest
The ESA's Gaia mission aims to record the positions, movements, distances and brightness of almost two billion celestial bodies. Current data from more than 150,000 asteroids has enabled researchers to search for the typical wobble of a double asteroid, which is caused by the drag of the asteroid's companion.

According to Liberato, the new discovery shows: "There are many more asteroid moons just waiting to be found."

40 million observations per day
To measure the Milky Way, "Gaia" has two telescopes with the largest digital space camera to date with almost one billion pixels. Each of the approximately one billion target stars will be monitored on average around 70 times over a period of five years and its exact position and path through space will be measured. This corresponds to around forty million observations per day.