Scientists: the Galaxy can settle the millions of «abandoned» moons

© Fotolia / Vadimsadovski planet in the emptiness of spaceScientists: the Galaxy can settle the millions of «abandoned» moons© Fotolia / Vadimsadovski

. Interstellar space may inhabit countless moons, thrown planets outside their star system in the early stages of their development, according to a paper accepted for publication in the Astrophysical journal.

«According to our calculations, most of the moons is on unstable orbits in a time when the planets interact strongly with each other. Only 10-20% of them satellites, the others are ejected into the interstellar medium collide with the gas giants or become independent «planets» orbiting the star,» write Jonathan Lunin (Johathan Lunine) from Cornell University (USA) and his colleagues.

Over the past two decades, astronomers have discovered nearly four thousand planets orbiting distant stars, many of whom live in large enough star systems, almost equivalent to a Solar system in complexity. During all this time was one of aktolun and several candidates for the role of orbiting «planets-derelicts» thrown outside star systems.

The first satellite of a planet outside the Solar system was opened by two well-known planetary scientists David Kipping and Alex Tichy, in July of this year. The moon revolves around the planet Kepler-1625b, the analogue of Saturn, whose radius is about two times smaller than Jupiter and 6 times more than Earth. It makes one revolution around the sun in approximately 287 days and is almost in the middle of the «zone of life».

Its discovery and the absence of other moons in data «Kepler» has forced astronomers to think about how many extrasolar planets have satellites, whether to look for traces of life on the surface and why for all time of observations was open only one of them.

To answer this question Lunin and his colleagues created a computer model of a typical star system in which the planets and the moon just began to form. Watching her evolution over several tens of millions of years, scientists have tried to understand the behavior of newborn «cousin» of the moon and how the architecture of their «planetary family» affects their behavior.

These calculations revealed an interesting feature in the life of the satellites of exoplanets – the vast majority, about 90%, disappears during one of the most turbulent stages of development of stellar systems, newborn babies of the planet come together and begin to «jostle» with each other, trying to throw the «neighbors» in space.

Survive, as scholars have noted, only a small number of moons, which have very specific characteristics – they must have certain dimensions and be located at a certain distance from the planet, near which they were born, so they can survive this stage of planetary formation.

According to Lunin and his colleagues, it well explains why astronomers were able to access just like the moon – most of them were or are «catapulted» into the interstellar medium, or destroyed during such gravitational interactions. This, in turn, means that the void between the stars can be millions of such objects – for every thousand stars have about a hundred of such «abandoned» the moon.

If this is true, then absoloni is found not only in the vicinity of the stars that already have planets, but in interstellar space, the scientists conclude.