This illustration shows Oumuamua racing toward the outskirts of our solar system

Is First Well-known Oumuamua an Interstellar Asteroid or Comet?

The most well-known object Oumuamua got an unexpected boost in speed, NASA’s scientists have confirmed using observations from Hubble Space Telescope and ground-based observatories.

“Our high-precision measurements of “Oumuamua’s position revealed that there was something affecting its motion other than the gravitational forces of the Sun and planets,” said Marco Micheli of ESA’s (European Space Agency) Space Situational Awareness Near-Earth Object Coordination Centre in Frascati, Italy, and lead author of a paper describing the team’s findings.

Analyzing the trajectory of the interstellar visitor, co-author Davide Farnocchia of the Center for Near Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory (JPL) indicated that the object’s behavior is a comet.

“This additional subtle force on ′Oumuamua likely is caused by jets of gaseous material expelled from its surface,” said Farnocchia. “This same kind of outgassing affects the motion of many comets in our solar system.”

The team estimates that ′Oumuamua’s outgassing may have produced a very small amount of dust particles – enough to give the object a little kick in speed, but not enough to be detected.

“The more we study ′Oumuamua, the more exciting it gets,” Meech said. “I’m amazed at how much we have learned from a short, intense observing campaign. I can hardly wait for the next interstellar object!” Karen Meech, an astronomer at the University of Hawaii’s Institute of Astronomy and co-author of the study.

Oumuamua, less than half a mile in length, now is farther away from our Sun than Jupiter and traveling away from the Sun at about 70,000 mph. In only another four years, it will pass Neptune’s orbit on its way back into interstellar space.

Because ′Oumuamua is the first interstellar object ever observed in our solar system, researchers caution that it’s difficult to draw general conclusions about this newly-discovered class of celestial bodies.

 

Source: NASA