The comet Ison received on 15 November in the night sky over England. Maximum five kilometers in size is the fragile chunks of rock, ice and dust from the cold outer reaches of the solar system. Currently decides whether a “comet Ison” became known object C/2012 S1 can also defy the scorching heat of the sun.
With more than 600 kilometers per second Ison will happen on Thursday our day-star in an almost 180 degree tight turn and approach the 6000 degree hot surface up to 1.1 million kilometers, which corresponds to less than a solar diameter. Withstands Ison this hell ride, he could then be visible even to the naked eye in the sky and deliver a celestial event, as has not been experienced in Europe since 1997. At that time, the comet Hale-Bopp was weeks in the sky.
Isons strange train
Ison electrified for months professional and amateur astronomers who track every stage of its development. Spectacular – and plenty of half-baked – Forecasts already circulated shortly after the astronomers Vitali Nevski and Artyom Novichonok the comet on 21 September 2012 had discovered as inconspicuous point of light on sky photographs of the Russian Kislovodsk Observatory. Because the trajectory of Ison is unusual, true most of the comet but a respectful distance from the Sun.
Ison most comets come from the “Oort Cloud”, a Dutch astronomer Jan Hendrik after the Oort named, previously only suspected comet reservoir at the edge of the solar system. Sometimes the objects pass through interference with other equipment close to the sun, but few go there so much up close and personal as Ison. In December 2011, the Comet Lovejoy (C/2011 W3) crossed the Sun in a mere 140,000 kilometers distance, half the Earth-Moon distance. Lovejoy’s impressive tail, however, was only visible from the southern hemisphere.
The best chance to see with their own Ison, made the early morning at the start of twilight between the 4th and 14 December. The map shows the view of the sky in the south-west, about an hour before sunrise. While the cometary orbits follow Kepler’s laws and therefore can be predicted quite accurately, the brightness of a comet development hardly predict – especially not when he gets like Ison for the first time in the vicinity of the Sun
. A huge tail
How bright is a comet as it approaches the sun, depends on how much evaporates from its ice by the heat and the gas shoots out of the comet’s nucleus. Because visible from Earth is only the bright glowing comet coma, a cloud of gas and dust, which completely envelops the core. The charged particle wind of the sun and the pressure that it exerts on the light dust of the coma, is ultimately responsible for the identifying of a comet: its tail. Ison already adorned the end of November at least eight million kilometers long gas tail, his coma reached a diameter of more than 100 000 kilometers -. Ten times the Earth’s diameter
After two brightness eruptions on 13 and 19th November Ison was already seen for experienced observers with simple binoculars. In the course of this week Ison is not observed in the daytime from the Earth, the solar observatories stationed in space Stereo and Soho, however, researchers can pursue his fire ride. At the beginning of the week, the signs that the comet nucleus already falling apart on approach to the sun were increasing. Whether and how bright Ison during the first week of December in the morning sky is visible, the experts can not reliably predict at present.
learning for Europe’s Rosetta Project
breaking for astronomers would not be a disaster – but a rare opportunity to examine the interior of a “fossil” from the early days of our solar system in more detail. The material of the icy messengers from the Oort cloud has not changed since 4.5 billion years ago. The findings should also benefit researchers from the European Space Agency ESA, when the probe Rosetta swing in the summer of next year in an orbit around the comet Churyumov-Gerasimenko and the lander “Philae” will settle on the comet’s surface.
When, where and how?The best chance to see Ison with my own eyes, made the early morning at the start of twilight between the 4th and the 16th December. Whether Ison, however, developed a magnificent tail, is still uncertain. During the month the comet follows its trajectory towards the north, from mid-month onwards he is also seen in the constellation of Hercules in the evening sky. However, Ison removed again from the sun, its brightness decreases. In addition, in the second half of December disturbs the bright moonlight. At Christmas Ison might be using binoculars or a telescope continues to track in case of his survival.
On 27
December Ison will pass Earth at a distance of 65 million kilometers.
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