Early comet detected
14 Dec 2017 by qmjwtjwqdb.d qmjwtjwqdb.d
Astronomers have identified a comet 1.5 billion miles from the Sun – a feat never achieved before – using the Hubble telescope.
Astronomers have identified a comet 1.5 billion miles from the Sun – a feat never achieved before – using the Hubble telescope. No other comet has ever been viewed at such as distance before and this find will enable scientists to monitor the developing activity of a comet in never-before-seen detail. C/2017 K2 (PANSTARRS), or K2, is currently beyond Saturn’s orbit and has been travelling for millions of years.
Professor David Jewitt, from UCLA and project leader, said: “Because K2 is so far from the sun and so cold, water ice there is frozen like a rock, and we know for sure that the activity – all of the fuzzy stuff making it look like a comet – is not produced by the evaporation of water ice, as it is in other comets.”
K2’s orbit indicates that it originated from the Oort Cloud, a large region thought to contain billions of comets. Slightly warmed by the Sun, it has developed an 80,000 mile wide fuzzy cloud of dust, called a coma, containing a tiny, solid nucleus of frozen gas and dust. The scientists’ observations are the earliest signs of activity seen from a comet entering our Solar System’s planetary zone for the first time.
From the observations made, the astronomers think that the Sun is heating frozen gases such as oxygen, nitrogen and carbon dioxide. As a result, the coma is potentially formed when these gases lift off from the comet and release dust. Professor Jewitt said: “I think these volatiles are spread all through K2. But the volatiles on the surface are the ones that absorb the heat from the sun, so, in a sense, the comet is shedding its outer skin."
The majority of comets are discovered much closer to the Sun, and as a result, most volatile gases have already escaped. Due to observing K2 at such an early stage, these gases remain, leading scientists to think this is the most ‘primitive’ comet detected. The comet is also unusual as it has no tail, commonly seen in other comets. This is however, expected to change as the comet nears the Sun.
The paper was published in Astrophysical Journal Letters.
