Comet Ison (circled) on course to the Sun (right)
Comet Ison (circled) on course to the Sun (right) .

Astronomers tracking Comet Ison have their fingers crossed that at least some fragments may be left of the heavenly body after its close encounter with the sun.

The scientists were hopeful that Ison, dubbed the "Comet of the Century", could help unlock secrets about the creation of planet Earth, if it survived perohelion - its closest point to the sun.

Ison was officially declared dead when its nucleus and tail vanished from a tracking video but scientists cannot know the fate of Ison for sure until January when it would have been due to have circled the sun and return to view.

The cause of its suspected destruction was soaring temperatures of up to 2,000C and the huge gravitational pull exerted by the sun.

But reports of Ison's demise may have been exaggerated, said some scientists. A small piece of the 2km-wide comet may have survived.

Nasa's Karl Battams said it would be just like Ison to come back from the dead.

"We've been following this comet for a year and all the way it has been surprising us and confusing us," he said.

"It's just typical that right at the end, when we said, 'yes, it has faded out, it's died, we've lost it in the sun' that a couple of hours later it should pop right back up again," he told the BBC.

"We would like people to give us a couple of days, just to look at more images as they come from the spacecraft, and that will allow us to assess the brightness of the object that we're seeing now, and how that brightness changes.

"That will give us an idea of maybe what the object is composed of and what it might do in the coming days and weeks."