systeme solaire destabilise survol etoile

In the very long term, the solar system could be destabilized by the passage of a star

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The passing of a nearby star could completely disrupt our solar system, but not yet. Canadian researchers have carried out nearly 3,000 simulations to observe that this event could modify Neptune’s orbit by 0.1%, which would be enough to expel planets from the solar system, or cause them to collide. However, this type of phenomenon only occurs once every 100 billion years or so.

Within the solar system, any change in the planetary trajectory can have obvious repercussions on its evolution. Ever since Newton formulated his universal law of gravity, the long-term stability of our system has been a concern of astronomers for centuries. However, the architecture and evolution of planetary systems are determined in part by stellar flybys, even if their effect may be minimal.

In this context, Garett Brown and Hanno Rein of the University of Toronto have become interested in colliding nearby stars that are too weak to immediately destabilize the solar system but strong enough to measurably perturb the dynamical state of the system. solar. If a star were to come within a few billion kilometers of our system, what planetary trajectories would be altered?

2880 simulations of stellar flybys and their effects 4.8 billion years later

In all, Canadian researchers conducted 2,880 simulated flybys of stars near the solar system. Your results are published on the pre-publication platform arXiv. Depending on the mass and distance of the tested star, the intensity of the disturbances in the system varied, and this up to 4.8 billion years later. In fact, some simulations stopped earlier, when a planet was destroyed or expelled from the solar system. Therefore, other outages are likely to occur after this date.

We perform long-term integrations and show that even small perturbations from stellar flybys can influence the stability of planetary systems during their lifetime. the researchers write. ” We find that small perturbations in the orbits of the outer planets are transferred between planets, increasing the probability of destabilization of the inner planetary system. “.

Our results for the solar system show that relative perturbations of Neptune’s semi-major axis [la planète la plus éloignée du système solaire] of the order of 0.1% are strong enough to increase the probability of destabilizing the solar system by an order of magnitude “, they specify. This corresponds to a change in Neptune’s position of about three times the distance between the Sun and Earth.

Most of the simulations generated planet collisions.

Of the 2,880 simulations performed, 1,920 caused probable and measurable instability and 960 induced disturbances too weak to measure. Of the likely simulations, most resulted in collisions between Mercury and Venus, closest to the Sun, and 26 ended in system disaster. Some simulations have shown an ejection of Uranus, Neptune, or Mercury from the solar system, and one experiment has even induced a collision between Earth and Mars!

The path of the dynamic instability of the solar system is ultimately determined by chaos. writes Garrett Brown in a tweet. ” However, the most likely path to instability is a resonance between Mercury and Jupiter leading to an increase in Mercury’s eccentricity. This can lead to a collision with Venus. “.

Fortunately, the researchers conclude that this type of phenomenon only occurs once every 100 billion years or so. Weak perturbations initially shake the system slightly, with instability occurring only millions to billions of years after the star’s passage.

Source: arXiv

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