The threat of centaur solar system objects to Earth

Astrophysicists Mattia Galiazzo and Rudolf Dvorak of the University of Vienna, in collaboration with Elizabeth A. Silber (Brown University, USA), studied the long-term development of the centaurs, the minor bodies of the solar system initially having orbits between Jupiter and Neptune. The researchers estimated the number of close encounters and impacts with terrestrial planets after the so-called last-minute heavy bombing about 3.8 billion years ago, as well as the possible crater sizes that would occur after a collision with the Earth and other terrestrial planets. . The report is published in Monthly Notices from the Royal Astronomical Society.

The centaurs come mainly from trans-Neptunian objects and are among the sources of objects close to the Earth. It is therefore crucial to understand their orbital evolution, which can in some cases lead to a collision with terrestrial planets and produce catastrophic events. The researchers studied the orbital evolution of the centaurs to the internal solar system and estimated the number of close encounters and impacts with terrestrial planets after the late heavy bombardment, assuming a population of centaurs at the same time. 39, stable state. "We also estimate the possible size of the craters.The centaurs can also become active comets, because of the presence of water on many of them.We have also calculated the approximate amount of craters. water rejected on Earth, which is comparable to the quantity We also found sub-regions of the Centaurs from where the potential impactors come from, "says Mattia Galiazzo.

The crater size can reach several hundred kilometers in diameter. however, given the known population of centaurs, the majority of craters would be smaller than 10 km. For all planets and an average impactor size of about 12 km in diameter, researchers estimate on average two impacts since the late heavy bombardment for the Earth and between one and two for Venus. This "bombardment" is less intense (at least one-tenth) than the asteroid impacts originating in Mars and Jupiter. However, centaurs are on average much faster and more massive. For smaller centaurs (for example, with a diameter> 1 km), the frequency of impact is much higher, about one every 14 Myr for Earth, 13 Myr for Venus and 46 for Mars. The researchers discovered that about half of centaurs can enter the region of the earth's planet and about 7% of them interact with terrestrial planets. Centaurs could be the cause of catastrophic events on Earth.

These results make an important contribution to the analysis of catastrophic events of extraterrestrial origin, which also occur on planets like Mars and Venus. "Our work also provides the framework to better understand past events and their impact on life on Earth and other terrestrial planets," said Galiazzo. For example, Dvorak said: "Such events could have a direct impact on life by destroying it (for example, the Earth) or by creating favorable conditions (for example, hydrothermal activity) for new Life forms are formed, and our results offer more answers about the evolution of the current solar system. "

Silber also notes that the Centaurs could provide water to Mars by collision. Recent missions confirm the presence of water on Mars.

Explore further:
Origin of the rings of the minor planets revealed

More information:
M A Galiazzo et al, The Centaurs' threat to terrestrial planets and their orbital evolution as importers. Monthly Notices from the Royal Astronomical Society (2018). DOI: 10.1093 / mnras / sty2614