(ORDO NEWS) — Mars – a magnificent, red planet – perhaps once was even more dazzling. A new study provides even more evidence that he was surrounded by a stone ring.
A new clue lies in Deimos, the smaller of the two Martian satellites. It revolves around Mars with a slight slope relative to the equator of the planet – and this may well be the result of gravitational fraud caused by the planet’s ring.
Ring systems are not so rare. When you imagine rings around planets, your mind immediately shows Saturn, no doubt – but half of the planets in the solar system have rings, Saturn, Uranus, Neptune and Jupiter. The dwarf planet Haumea and the centaurs Chiron and Chariclo also have rings.
In 2017, a couple of researchers suggested that Mars also once had a ring. They simulated the larger of the two Martian moons, Phobos, and discovered that it could have formed after the asteroid crashed into Mars, sending debris into space, forming a ring, which then stuck together into the earlier form of Phobos, which was much more massive, than today.
Now the researchers have added Deimos – and the results are completely consistent with the previous model.
“The fact that the orbit of Deimos does not quite coincide with the equator of Mars was considered unimportant, and no one tried to explain it,” says astronomer Matia Chuck from the SETI Institute.
“But as soon as we had a new idea, and we looked at it with a fresh look, the orbital inclination of Deimos revealed his great secret.”
The orbital inclination of Deimos is small – only 1.8 degrees from the equator of Mars. In addition, its orbit is quite normal – it revolves around Mars every 30 hours or so, with extremely low eccentricity.
But something strange happens to Phobos. It is much closer to Mars, in orbit 7 hours 39 minutes, and is approaching Mars at 1.8 centimeters per year.
Within 100 million years, Phobos is expected to reach the Roche limit, the distance from Mars at which the tidal forces of the planet will tear the satellite apart.
Most of the garbage forms a ring, and after that it can turn into a smaller, new Phobos.
This, according to a 2017 study , could happen several times in the past. And then comes Deimos.
Using numerical modeling, Chuck and his team tried to simulate how such protophobos would affect the inclination of Deimos’s orbit. And they reached protophobos, 20 times its current mass, which would enter into an orbital resonance of 1: 3 with Deimos at a distance of 3.3 of the radius of Mars, which led to a slight inclination of the orbit of the latter.
“This process happened about 3.5 billion years ago,” he said. “This is in perfect agreement with Hesselbrock and Minton’s calculations when Mars had a satellite 20 times the mass of Phobos.”
The study was presented at the 236th meeting of the American Astronomical Society and accepted for publication by The Astrophysical Journal Letters. Currently available on arXiv .
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