ناسا تاييد کرد : سفر 5.5 ميليون ساله دنباله دار آيسان به پايان رسيد

 Comet ISON is confirmed dead after brush with Sun

 A comet that grabbed attention worldwide for being likened to a massive snowball in space did not survive its brush with the Sun last week, NASA confirmed on Tuesday.

"Though the exact time of ISON's death is uncertain it does appear to be no more. All that is left is a cloud of debris without a nucleus," C Alex Young of the NASA Goddard Space Flight Center told AFP in an email.

Dubbed the "Christmas Comet," the icy giant described as a massive, dirty snowball skimmed past the Sun at a distance of just 730,000 miles (1.17 million kilometers) around 1830 GMT on Thursday.

It had been estimated that ISON would undergo temperatures of 4,900 degrees Fahrenheit (2,700 Celsius)and lose three million tonnes of its mass per second as it made its journey around the sun.

Most astronomers had predicted the comet, with an estimated diameter of some 0.75 miles (1.2 kilometers), would not survive the flypast.

Still, some observers had held out a sliver of hope that the 4.5 billion-year-old comet might have survived.

Karl Battams, a scientist at the Naval Research Laboratory, wrote a brief obituary for the comet, formally known as C/2012 S1 (ISON) after the telescope called the International Scientific Optical Network used by the Russian astronomers who spotted it in 2012.

"Never one to follow convention, ISON lived a dynamic and unpredictable life, alternating between periods of quiet reflection and violent outburst," Battams wrote.

"Survived by approximately several trillion siblings, Comet ISON leaves behind an unprecedented legacy for astronomers, and the eternal gratitude of an enthralled global audience."