The fate of the Comet ISON has worried astronomers that analyzed with attention its shifting from the Sun during the day of Thursday. Two hours after ISON got closer at little more than 1 million kilometers of the planet’s surface a distance considered small, whereas it is less than the diameter of the Sun, ISON still didn’t appear in the area monitored by space probes Soho and Stereo, which filmed the events around the Sun.
The comet ISON passed the Sun at an astounding rate, which reached 1.4 million kilometers per hour.
The initial findings of experts indicated that ISON, a giant snowball and stellar dust, came from the edge of the Solar system, has not survived temperatures of several thousand degrees Celsius during the approach near the Sun and that this heavenly body disintegrated.
It would have been a tragic fate, which some astronomers have predicted it, but which would have cancelled any chance of being able to observe the Comet in the night sky in early December, with the naked eye in the best case, or with binoculars.
On Friday, however, to the surprise of specialists, a bright spot made its appearance on the images captured by the Soho space probe, exactly in the place where it was expected the comet’s ISON trajectory.
“I could see no more than a very small tail that appears to come from the debris of the comet dust, and, then, little by little, a brilliant condensation reappeared on images,” explained Dominique Bockelée-Morvan, astronomer and director of research at the National Center for scientific research in Paris Observatory affiliate.
This “shimmering dew” is a sign that the comet’s nucleus-or what’s left of it-became active and began to emit gases and dust, being warmed by the Sun.
“A brilliant vein material, which moves away from the Sun, appeared on the pictures from the Solar and Heliospheric Observatory, operated by the European Space Agency and NASA, on the night of Thursday to Friday,” it is said in a statement posted Friday on the NASA website, quoted by Reuters news agency.
“We don’t know yet whether the debris remaining from the Comet or if part of the nucleus of Comet survived” NASA says.
So far it is too early for that astronomers can tell if ISON remained intact or has been fragmented and indicate the percentage of the mass of the original has been preserved, but in any case, the remaining mass is sufficient to form a nucleus with a visible activity.
Experts will also have to explain why comet ISON has remained invisible for such a long period of time after passing near the Sun. One hypothesis is that the temperature in the area was so high that the dust particles were burned and vaporized instantly and, thus, for wake of the comet hadn’t left any material to disperse light making visible the comet.
The core itself is still invisible, as it is a very dark and should have, according to experts, a diameter of less than one kilometer. Moving away enough from the Sun, the temperature has dropped enough that dust could survive.
ISON has captured the attention of the astronomical community after its discovery in September 2012 by two Russian astronomers, since it is a proof of the origin of the solar system formed 4.5 billion years ago. Comet escaped only after a few million years from the Oort Cloud, a kind of “parking” of comets at the edge of the Solar System, halfway between the Sun and the nearest star.
Some astronomers originally thought ISON was a large comet with a nucleus having a diameter of several kilometers. But when the comet passed close to Mars, NASA’s Mars probe was able to photograph and indicated a maximum diameter of only 1.2 km, the lower diameter of the comet.
During the observations of the ISON comet that was detected in the Solar System, astronomers have had a lot of time to analyze it. Their measurements showed especially that the comet nucleus was surrounded by a cloud of carbon dioxide (CO2).