New evidence of a past Mars belt

The latest research provides evidence that Mars has in the past been surrounded by a material belt. What happened to that belt?

New evidence is hidden in the Deimos satellite - the smaller of the two natural satellites of Mars. Deimos orbits Mars with an angle not large compared to the planet's equatorial plane. This tilt may be the result of the gravitational effect from the material belt.

The ring system is not a rare phenomenon. The most spectacular material belt belongs to Saturn, but such structures also appear around Uranus, Neptune and Jupiter. The dwarf planets Haumer and the asteroid Chiron and Chariklo are centaurs (micro-planets) that also have rings.

Mars once had a material belt.

In 2017, some scientists hypothesized that Mars had a physical ring in the past. They performed simulations for the satellite Phobos - the larger satellite of Mars and discovered that it could form in the asteroid collision result with Mars. The fragments of matter thrown into outer space gradually form a belt, and from there Phobos appear. Now, scientists have also studied the Deimos satellite, and the results appear to be consistent with previous analysis.

' Deimos ' orbit is not in the same plane as the Martian equator and is thought to be unnoticeable, and no one has tried to explain it. However, when we came up with a new idea and observed this phenomenon from a new perspective, we realized that Deimos 'orbital deviation revealed many mysteries' - astronomer Matija Cuk at the Search Institute extraterrestrial intelligence (SETI Institute), said.

The deimos orbit angle is not large - only 1.8 degrees off the Martian equator. In addition, the orbits of this satellite are completely normal: Deimos orbits Mars within 30 hours with very little eccentricity. However, Phobos is different. This satellite is closer to Mars and orbits Mars once every 7 hours 39 minutes. Moreover, each year Phobos approaches 1.8cm of Mars. 

Thus, it is possible that within 100 million years, Phobos will exceed the Roche limit - the distance from Mars that if overcome, Phobos will be shattered by Mars tidal force. A large portion of the fragments of Phobos form a belt; however some debris may turn into new, smaller satellites. According to research from 2017, that phenomenon may have happened several times in the past.

Using digitized simulations, Matija Cuk's team tried to model how the 'pre-Phobos' debris impacted on Deimos orbits. Scientists have focused on 'pre-Phobos' fragments with masses greater than the current Phobos mass. This fragment resonates with Orimos orbit at a distance of 3.3 times the radius of Mars. This phenomenon makes the Deimos orbit plane slightly skewed from the equator of Mars.

'The deimos orbit event took place about 3.5 billion years ago,' ' said Matija Cuk.

The Phobos satellite was probably formed about 200 million years ago. Scientists intend to verify that. The Japan Space Agency JAXA plans to launch a space probes on Phobos by 2024.