K2 was discovered by Hawaii's Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in May 20 17, but it was only our first contact-thanks to Hubble telescope-that we were able to observe the meaningful details of this comet in many aspects.
To the surprise of astronomers, although this comet is still somewhere between the orbits of Uranus and Saturn, it has entered an active state. At this position, the surrounding temperature is only MINUS 400 degrees Fahrenheit, and the intensity of the sun is only 1/255 on the earth. However, this comet has begun to de-ice. According to the news report, the observation of Hubble telescope "shows for the first time the earliest signs of activity that can be observed after a comet enters a planet in the solar system".
K2 is currently moving towards the sun, and now it is close enough to produce dust and gas clouds, which is the so-called "comet tail". At present, the observed tail diameter is about 80,000 miles (6.5438+0.28 million kilometers).
"K2 is so far away from the sun and so cold, I believe it is actually a phenomenon-all vague things make it look like a comet-that is, it is different from other comets, and they are produced by the gasification of ice formed by water."
David Jewett, who is studying comets at UCLA, explained at a news conference. "On the contrary, we believe that this phenomenon is caused by the sublimation of an ultra-volatile substance (solid directly turns into gas) when K2 first enters the planets in the solar system. This is what makes it special. This comet is so far away from us that it is incredibly cold that the water ice there is frozen like a rock. "
Jewitt said that the observation of special volatile gas mixtures including oxygen, nitrogen, carbon dioxide and carbon monoxide made K2 "the most primitive comet we have ever observed".
K2 made a long journey inward, which originated from Oort Cloud, a spherical shell containing billions of comets, with a diameter of nearly one light year. These rock balls made of ice, dust and gas can be traced back to the formation of the solar system 4.6 billion years ago.
The comet has not yet formed a tail-at least not yet. K2 will reach its closest point on July 14, 2022, when it will be just outside the orbit of Mars and 2.677 astronomical units (250 million miles) away from the sun. Whether K2 can be observed by naked eyes after five years is still inconclusive.
relevant knowledge
C/20 17 K2 is an aperiodic comet with hyperbolic orbit, which was discovered in May 20 17 outside Saturn's orbit at a distance of 16.09 AU from the sun. The pre-discovery image of 20 13 was found in July. It has been in the constellation Draco since July 2007. As of April 20 18, the current 3σ uncertainty of the comet from the sun is 30000km.
Author: George Dvozski
FY: Yao Yao
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