In 2017, astronomers spotted the first interstellar visitor sprinting through the solar system. Now, astronomers think we are again visited by another celestial body from a neighboring star system.
Comet From Another Star System
Gennady Borisov, an amateur astronomer from Ukraine, spotted the object at a Crimean Peninsula observatory on Aug. 30. Scientists who used bigger telescopes to follow up on Borisov's discovery found that the object is several kilometers across and has a highly eccentric projected path. It was also found to be a comet based on its fuzzy appearance.
Named C/2019 Q4 (Borisov), the object is traveling at a speed of about 93,000 miles per hour (150,000 kilometers per hour) toward the sun. Astronomers said this velocity suggests the object is likely from another star system. NASA has said the comet is likely an interstellar object.
"Half a year ago, I made a new telescope. And with the help of it, I discovered this unique comet," Borisov said. "I would be glad if such an interesting space object gets my name."
Scientists can already detect its coma, the fuzzy haze surrounding the comet's nucleus that forms when the comet passes close to the sun. The comet is expected to zoom past the sun in December and will keep going until it is back in interstellar space.
The eccentricity of C/2019 Q4's path suggests that it will only visit the solar system once.
Opportunity To Study An Interstellar Object
Because the comet is still on approach to Earth and is expected to be visible with professional telescopes well into next year, researchers will have more time to make observations.
With more time to study the object, scientists may even find clues about the comet's origins from the coma of debris that it sheds. The object will dissipate from view by October 2020.
Researchers had limited opportunity to study Oumuamua, the solar system's first known interstellar visitor, because it was only detected when it was already on its way out of the solar system.
"This thing should be observable for a year," said International Astronomical Union's Minor Planet Center interim director Matthew Holman. "We get to see one little bit of another solar system."