I’ve held off posting about Comet ISON’s fate following its close encounter with the Sun as conflicting reports about whether it survived the encounter or not have been flying about since last night.
The giant ball of ice and dust was initially declared dead when it failed to re-emerge from behind the star with the expected brightness. But recent pictures have indicated a brightening of what may be a small fragment of the comet.
While the comet initially appeared to have disintegrated, a couple of hours after close approach, a fragment did indeed appear to survive and what was left of the comet began to brighten appreciably.
This video made by observing campaign member John Maclean shows the comet slicing toward the sun and then something — apparently ISON — emerging from the other side. Maclean is a fellow of the Royal Astronomical Society at Norman Lockyer Observatory Sidmouth in Devon, England.
Astronomers admit to being surprised and delighted, but now caution that anything could happen in the coming hours and days. This remnant of ISON could continue to brighten, or it could simply fizzle out altogether.
“We’ve been following this comet for a year now and all the way it has been surprising us and confusing us,” said astrophysicist Karl Battams, who operates the US space agency-funded Sungrazing Comets Project.
“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 BBC News.
How much of the once 2km-wide hunk of dirty ice could have survived is impossible to say. Passing just 1.2 million km above the surface of the Sun would have severely disrupted ISON. Its ices would have vaporized rapidly in temperatures over 2,000C. And the immense gravity of the star would also have pulled and squeezed on the object as it tumbled end over end.
Astronomers want couple of days to assess images coming in from various solar missions before they make a final call on the comet’s fate.
Top video: These images from NASA’s Solar Terrestrial Relations Observatory and the ESA/NASA Solar and Heliospheric Observatory show Comet ISON growing dim as it made the journey around the sun. The comet was not visible at all in NASA’s Solar Dynamics Observatory. The comet is believed to have broken up and evaporated.
While this means that Comet ISON will not be visible in the night sky in December, the wealth of observations gathered of the comet over the last year will provide great research opportunities for some time. One important question will simply be to figure out why it is no longer visible. Credit: NASA/SDO/ESA/SOHO/GSFC.
Filed under: Comets
