Bokeyuan: This article is astronomy
As we all know, comets have a very "temper" because comets venture to approach the sun. When comets submerged from the outer edge of the solar system, these cold celestial bodies began to spew out gas and dust. The glowing burst of comets can create spectacular sights that make the night sky shine brightly over days, weeks, or even months. But comets were not born this way, and comets have been debated for a long time from their initial formation location to their inner paths. Planetary scientists are very interested in comets, because comets may be the most primitive residue left since the birth of the solar system.
In a study published in the journal Astrophysics, a team of researchers including Katherine Volker and Walter Harris from the University of Arizona's Lunar and Planetary Laboratory reported that an orbital region was found outside Jupiter, which acts as a "comet entrance." This path will be called the Centaur celestial bodies from regional funnels of giant planets (Junessa, Saturn, Uranus and Neptune) to the solar system, where they can become frequent visitors near the Earth from a cosmic perspective. The entrance is roughly shaped like a hypothetical donut circling the area and was discovered as part of a simulation of a Centaur, a small ice body that moves in a chaotic orbit between Jupiter and Neptune.
Ice-cold thief on any path
Centaur celestial bodies are believed to originate from the Kuiper Belt, a region inhabited by frozen objects outside Neptune and extending to about 50 astronomical units (50 times the average distance between the sun and the earth). Close contact with Neptune pushes some of these comets into internal orbits and becomes Centaur celestial bodies, which are the source of about 1,000 short-period comets moving rapidly around the inner solar system, also known as Jupiter series comets, or JFCs, including comets visited by spacecraft missions such as Tempel 1 (Deep Impact), Wild 2 (Stardust), and 67P/Churyumov-Gerasimenko (Rosetta). One of the co-authors of
and an assistant scientist who studies Kuiper Belt objects, planetary dynamics and exoplanets, said: The chaotic nature of their orbits blurs the exact paths of these centaur bodies becoming JFC. This makes it difficult for us to figure out where they really come from and where they might go in the future. Centaur celestial humans often do not stay nearby under the gravitational fields of several nearby giant planets Jupiter, Saturn and Neptune, thus forming a community with high turnover. They rattle for millions of years, perhaps tens of millions of years, but none of them even approached when the solar system formed.
Where will comet die?
Now we know that there are 300 centaur objects that can be seen through telescopes, but this is just the tip of the iceberg, with an estimated 10 million such objects. Most of the centaur objects we know were discovered before the CCD appeared, plus the need for computer help to search for these objects, but there is a big deviation in observation, because small objects are simply not bright enough to be detected. Each movement around the sun causes more wear on the comet until it eventually disintegrates, in close contact with the planet thrown out from the inside of the solar system, or its volatiles (mainly gas and water) are depleted, and usually most of the dust stays and covers the surface of the comet.
So the comet no longer heats up too much, it goes into a dormant state. According to some mechanism, the stable supply of "little comets" must replace comets that have already gone through their route, but until now, it is not known where they come from. To better understand how the Centaurs became JFC, the research team focused on creating computer simulations that could reproduce the orbit of 29P/Schwassmann-Wachmann 1 (SW1 for short). SW1 is a centaur object discovered in 1927 and is believed to have a diameter of about 65 kilometers. Although SW1 is too far from the sun and the water ice cannot melt, its high activity and frequent explosions have been plaguing astronomers.Its orbit and activity place SW1 in the evolutionary middle between other centaur objects and JFC
and the initial goal of observation is to explore whether the current situation of SW1 is consistent with the orbital evolution of other centaur objects. To achieve this, the team simulated the evolution of celestial bodies from outside Neptune's orbit, through this huge planetary region and within Jupiter's orbit. The research simulation results include several findings that fundamentally changed our understanding of comet evolution. More than one-fifth of the new Centaur objects that were simulated and tracked were found to enter a similar orbit to SW1 at some point in its evolution. In other words, although SW1 appears to be the only large centaur object known to occupy a few objects in the "Cradle of Comets", it is not a considered outlier, and is quite common for centaurs, according to new research.
In addition to the mundane nature of the SW1 track, these simulations lead to a more surprising discovery. The centaur objects passing through this area are the source of more than two-thirds of the Jupiter family comets, making this the main channel for the generation of these comets. Historically, the study hypothesis was that the area around Jupiter was quite empty and cleared by the gravity of the giant planet, but the results of the study tell us that there is an area constantly being fed. This continuous source of new objects may help explain the alarming speed of ice bodies colliding with Jupiter, such as the famous Comet Samuel-Levi 9 event in 1994.
Wordable Comet
Based on estimates and calculations of the number and size of ice objects entering, living and leaving the portal area, the study predicts that it will maintain an average number of approximately 1,000 Jupiter objects, not too far from the 500 discovered by astronomers so far. The results also show that the pass area triggers a rapid transition: Once the Centaur object enters it, it is likely to become a JFC within thousands of years, while in the blink of an eye in the solar system time frame. Harris and Volk believe that calculations suggest that the size of SW1 should enter the area every 50,000 years, so SW1 is likely to be the largest centaur in recorded human history to begin this transition.
In fact, SW1 may become a "super comet" within thousands of years. Researchers believe that in size and activity, it can rival Comet Haier-Bopp, one of the brightest comets of the 20th century, with SW1 having a 70% chance of becoming the most spectacular comet ever seen by humans. Our descendants may see a comet that is 10 to 100 times more active than Halley's Comet, except that SW1 will return every 6 to 10 years instead of every 75 years. If there were such a bright comet in the past ten thousand years, we would know it, and the researchers think it is a strong evidence that no similar events have occurred since at least since, because ancient civilizations not only recorded comets, they may also worship it!
Boke Park｜Research/From: University of Arizona
Reference journal "Astrophysics"
DOI: 10.3847/2041-8213/ab3fb3
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