Discovered by Hawaii’s asteroid terrestrial collision final warning system “ ATLAS” in December 2019“Comet Atlas (C / 2019 Y4)”Attracted attention in May 2020 as it could be observably bright before the sun’s closest approach, but about two months before the sun’s closest approach.Comet nucleus fragmentationIt was observed that it was done.This time, at the University of MarylandQuanzhi YeTheir research group presented the results of their research on the split and collapsed Comet Atlas.
■ Possibility of origin from the inside of a comet that split 5000 years ago
Orbit of Comet AtlasIs said to be as bright as SiriusGreat comet of 1844(C / 1844 Y1) andalmost the sameBecause it wasThe two comets may have been fragments of the same comet split in the past.Was pointed out from an early stage.Both cometsAbout 5000 years ago、The comet of the parent object (original object) split when it approached the Sun.Is believed to be. At that time, human beings who lived in the early days of civilization may have witnessed the splendid appearance of the comet, which is the mother celestial body.
On top of that, Mr. YePoint out questionsTo do.Of Comet AtlasComet that became the mother celestial bodyteeth,Approaching 0.25 astronomical units from the sun (about a quarter of the distance from the earth to the sun)It is believed that it was done.But after 5000 years, it returned to the center of the solar system.Comet Atlasteeth,Split while more than one astronomical unit away from the sunhave done.As part of the mother celestial bodyShould have endured the approach to the sun onceWhy did Comet Atlas split this time in a distant place?
The clue is“Hubble” Space TelescopeObtained by observation of. Ye et al.Fragment of split comet nucleus of Comet AtlasWhen I observedSome fragments collapse within a few days of splittingOn the other handAnother fragment exists for a few weeksIt is said that he was doing it. The research group may have split the comet nucleus of Comet Atlas because the gas ejected from the comet nucleus may have split due to centrifugal force due to the accelerated rotation speed, and the ice vaporized quickly and on a large scale. It raises the possibility of splitting like a fireworks display.
“Strength” was different depending on the fragmentTherefore, Comet AtlasDerived from the part where uneven ice was abundant inside the parent bodyThe research group speculates.The ice inside the mother celestial bodyProtected from the heat of the sun by the outer layerBecause it was doneMaybe it survived the closest approachThat’s why. 5000 years agoTiming when Comet Atlas split from the parent bodyAfter the mother celestial body is closest to the sunPossibly more than 1.5 astronomical units away from the sunHas been pointed out.The research group found that the ice is protected from the heat of the sun.Complex and non-uniform internal structureof,Possibility of comets up to several kilometers in diameterIt is supposed to indicate.
In 2020, when he observed the split Atlas comet, he said, “It’s really exciting. Fragmented comets usually don’t look dark, and collapses of this magnitude occur once or twice every ten years. Because it only happens once. “Opportunity to approach the cause of comet nucleus fragmentationI was hoping that I could get it. Although it did not become a bright comet that can be observed with the naked eye, Comet Atlas seems to have become a valuable comet that brings new insights to researchers.
Related: Confirmed a fragment of Comet Atlas that collapsed.Taken by the Hubble Space Telescope
Image Credit: SCIENCE: NASA, ESA, Quanzhi Ye (UMD), IMAGE PROCESSING: Alyssa Pagan (STScI)
Sentence / Takehiro Matsumura