Hubble photographed comets that are operating at a distance of 2.4 billion km

NASA's Hubble Space Telescope has just captured the most primitive comet ever. The strange thing is that this comet does not have a tail that lasts as long as other comets.

At a distance of 2.4 billion km, beyond Saturn's orbit, the Hubble Space Telescope captured a powerful active comet. Despite being far from the Sun, the heat caused the comet to develop a faint dusty gas cloud surrounding it and stretched to 129,000km.

The cloud surrounding the ice core is covered by dusty soil. This observation shows that comets work very early because normally comets approaching the Sun break the outer shell, freezing inside, and forming a tail.

Image of comet C / 2017 K2 by Hubble glass when it is 2.4 billion km away.(Photo: NASA, ESA, D. Jewitt (UCLA)).

This comet is called C / 2017 K2 (PANSTARRS) or "K2" , has traveled millions of years from its origin outside the Solar System, where the temperature is about -262 degrees Celsius. This comet shows that it comes from the Oort Cloud , a spherical region about 1 light-years across, containing hundreds of billions of comets.

Comets are icy objects that survived the formation of the Solar System about 4.6 billion years ago. The physical components within it, especially ice cores , are the most pristine and preserved parts of it for billions of years.

'K2 is very far from the Sun and very cold, but we know it is working due to the observation of a faint layer of gas surrounding it. But the surrounding gas is not created like other comets through evaporation and frost , "said researcher David Jewitt of the University of California, Los Angeles.

'Instead, we think this is due to the sublimation (a solid that converts directly into gas) of volatile substances when K2 enters the planetary region of the Solar System. The comet is too far away and it is so cold that the freezing ice freezes like stone, ' he added.

Based on Hubble's observations of the surrounding gas region around Comet K2, Jewitt says sunlight also heats volatile gases - such as oxygen, nitrogen, carbon dioxide and carbon monoxide - these gases Help cool the comet surface.

When these gases escape the comet, it will carry dirt and puree of rock along the outer space, creating a gaseous zone around the comet. Previous studies on the composition of comets near the Sun show that the evaporation process is similar.

'I think volatile gases have spread throughout comets K2 and have been there for billions of years ago. Maybe this comet has gone through all the objects present in Oort Cloud and is slowly breaking its outer shell.

Most comets are discovered when they come close to Jupiter's orbit, at this point most of them have evaporated to the outside and help us easily observe. But K2 is farther away than that and that is the most primitive comet that we have observed so far. "

K2 was discovered in May 2017 by the Panorama Survey and Quick Response Survey System (Pan-STARRS) in Hawaii, a sky survey project under the Observation of Close Objects Program Land of NASA. Jewitt uses Hubble glasses to observe this comet in late June.

Hubble's sharp eye revealed a clear picture of the gas cloud surrounding the comet and helped Jewitt estimate the size of the core to be less than 19 km, and the large surrounding cloud about 10 times the diameter of the fruit. Land.

Simulate the trajectory of comet K2, very large and it is on its way into the Solar System.(Graphics: NASA, ESA, and A. Feild (STScI)).

This cloud has probably been formed since the comet is located farther away from the Sun. Reviewing the old photos of this heavenly area of ​​the Canadian-French-Hawaii Telescope (CFHT) in Hawaii, Jewitt's group saw this comet with its surrounding halo but so faint that no one realized it. .

'We think comets have been working at least continuously for the past four years. Among the recorded data of CFHT shows that K2 has surrounded by gas clouds 3.2 billion km from the Sun, in the middle of the orbit of Uranus and Neptune. It has been operating since then, the more it gets inside, the more warm the Sun is, the more active it is, ' Jewitt added.

But the strange thing is that the comet K2 only has surrounding gas clouds, not a long tail like any other comet. The absence of this feature suggests that the escaping molecules are too large for the radiation pressure from the Sun to form a tail.

Astronomers will spend more time studying in detail about K2. In the next five years, comets will continue their journey deep into the Solar System, which is expected to reach Mars by 2022.

'We will continue to observe this particular comet. Because it has evaporated the gases inside the core from the Oort Cloud, it is predicted that it will have a spectacular tail if approaching the Sun even further , 'Jewitt said.

Jewitt added that NASA's James Webb Space Telescope is expected to be launched in 2019, will be able to measure the comet's inner core temperature, which will help astronomers estimate more accurately the size. its.