The time-sequence images from the Gemini Observatory, spanning early February through May, show remarkable activity on the part of Comet ISON despite its distance from the sun and Earth, they said.
The images provide clues as to the comet's overall behavior and potential to present a cosmic show after it passes close to the sun at the end of November and becomes an early morning spectacle from Earth in early December, an observatory release said Thursday.
The images, taken when the comet was just inside the orbital distance of Jupiter, emphasize the comet's dusty material already escaping from what astronomers describe as a "dirty snowball."
The images show the comet's well-defined parabolic hood in the sunward direction that tapers into a short and stubby tail pointing away from the sun.
"Our team, as well as astronomers from around the world, will be anxiously observing the development of this comet into next year, especially if it gets torn asunder, and reveals its icy interior during its exceptionally close passage to the sun in late November," Karen Meech at the University of Hawaii's Institute for Astronomy said.
Comet ISON "could still become spectacularly bright as it gets very close to the sun" she said, but added, "I'd be remiss if I didn't add that it's still too early to predict what's going to happen with ISON since comets are notoriously unpredictable."