A new image of the sunward plunging Comet ISON taken by NASA’s Hubble Space Telescope suggests that the comet is still intact despite predictions that it may disintegrate as the Sun warms it.
“In the image taken on October 9, the comet’s solid nucleus is unresolved because it is so small. If the nucleus broke apart then Hubble would have likely seen evidence for multiple fragments,” the Space Telescope Science Institute in Baltimore, which operates Hubble, said in a statement.
The image suggests the nucleus is almost certainly still intact — the coma or head surrounding the comet’s nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along.
Also, a polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.
The colour composite image was assembled using two filters. In the picture, the comet’s coma appears cyan, a greenish-blue colour due to gas, while the tail is reddish due to dust streaming off the nucleus.
The tail forms as dust particles are pushed away from the nucleus by the pressure of sunlight. The comet was inside Mars’ orbit and 285 million km from Earth when photographed.
Comet ISON will pass closest to the Sun on November 28 and if it survives it will make its closest approach to Earth on December 26.