When ISON failed to reappear after its close encounter with the Sun on Thanksgiving, NASA scientists thought it had disintegrated completely. Passing less than a million miles above the surface of the Sun would have exposed the comet to temperatures over 2,000 Celsius. However, a bright streak observed by the Solar and Heliospheric Observatory late on Thanksgiving could mean the comet’s nucleus is still intact.
The question remains whether it is merely debris from the comet, or if some portion of the comet’s nucleus survived, but late-night analysis from scientists with NASA’s Comet ISON Observing Campaign suggests that there is at least a small nucleus intact. Exactly how much of the previously 1.3 mile-wide hunk of dirty ice could have survived is impossible to say.
“We’ve been following this comet for a year now and all the way it has been surprising us and confusing us,” astrophysicist Karl Battams told BBC News. “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.”