COMET ISON New Details Emerge- due to rotational axis, new surface will be exposed to sun on close approach

[link to www.psi.edu]

“We measured the rotational pole of the nucleus. The pole indicates that only one side of the comet is being heated by the Sun on its way in until approximately one week before it reaches it closest point to the Sun,” said Planetary Science Institute Research Scientist Jian-Yang Li, who led a team that imaged the comet.

“Since the surface on the dark side of the comet should still retain a large fraction of very volatile materials, the sudden exposure to the strong sunlight when it gets closer to the Sun than Mercury could trigger huge outbursts of material,” Li said.

We measured the color of the coma, and found that the outer part of the coma is slightly redder than the inner part,” Li said. “This color change is unusual in comets, and seems to imply that the inner part contains some water ice grains, which sublimate as they move away from the nucleus.”

The expectation is high that Comet C/ISON will be much brighter and more spectacular than most other sungrazers when it puts on a show late this year.