A cigar shaped object identified to be as an asteroid or a comet by scientists

A European-led team makes the case in the Wednesday’s edition of the journal Nature. A visitor from another star system a cigar-shaped object which is briefly tumbling through our cosmic neck of the woods has now been identified to be as a comet from last year.

Telescopes first spotted this mysterious red-tinged object last October as it zipped through the inner solar system. Ever since then, astronomers have flip-flopped between deciding if it is a comet or an asteroid for our first confirmed interstellar guest.

Neither a coma nor a tail was spotted, on the  hallmarks of an icy comet. But Italian astronomer Marco Micheli and his team reported that the object’s path and acceleration are best explained not just by gravity, but also gases shedding from the comet.

The release of what’s believed to be as gaseous carbon monoxide, carbon dioxide and water applied only a tiny force on the object known as Muamua which is about 1,000 times smaller than the effect of the sun’s gravity  and has barely altered its path, the researchers said.

“But the team’s calculations were so precise that we could actually see the change in position caused by the outgassing,” said co-author Paul Chodas, manager of NASA’s Center for Near-Earth Object Studies at Jet Propulsion Laboratory in Pasadena, California.

“It’s a definitely an exciting discovery,” said Micheli of the European Space Agency.

Micheli said computer models suggest that the objects typically are ejected during the formation of planetary systems, and that most of these castaways should be comets as given their location is on the frigid outskirts of their systems. Only a tiny fraction should be asteroids, by scientists’ best calculations.

Had it been an asteroid, it would have been “extremely lucky to beat these odds” — or it would have underscored scientists’ misunderstanding of the early solar system, Micheli said.

Discovered by a telescope in Hawaii, Muamua is Hawaiian for a messenger from afar arriving first, or scout. It’s long gone, as the chances of knowing conclusively about what it was.

The University of Toronto’s Alan Jackson, who reported in March that Muamua which seems more likely to have come from a two-star system, and remains unconvinced of its true identity. “But this is certainly an interesting new piece of information for us to chew on,” he said in an email.