An unusual detected object that crossed the sky last month was a comet that originated outside our solar system, observations have confirmed, making it the second interstellar object observed crossing our solar system.
It has been named 2I/Borisov by the Minor Planet Center of the International Astronomical Union. And it is between 1.9 and 16 kilometers in diameter, say Karen Meech and her colleagues at the University of Hawaii.
Observations by the Solar System Dynamics Group at NASA’s Jet Propulsion Laboratory have supported that this comet has the most hyperbolic orbit of the thousands of known comets.
“The orbit is now sufficiently known and the object has an unmistakable interstellar origin,” according to an IAU statement, which has designated the object as the second interstellar object, 2I.
It was first seen on August 30, almost two years after the first interstellar visitor detected in our solar system, known as ‘Oumuamua, was found in October 2017. Interstellar means that the object originated outside our solar system.
Gennady Borisov saw a new comet while at the MARGO observatory in Crimea. The amateur astronomer used a 0.65-meter telescope that he built and saw something that looked like a comet with a short tail.
After this initial observation, the Scout system at NASA’s Jet Propulsion Laboratory also marked the object as possibly originating outside of our solar system. Scout evaluates recently found objects from the Minor Planet Center for dangers and possible trajectories.
Follow-up observations of the comet were made, including by Davide Farnocchia at NASA’s Center for Near-Earth Object Studies and the European Space Agency’s Near-Earth Object Coordination Center.
And soon we will have the opportunity to get to know the comet better, because it must enter the inner part of our solar system on October 26. To see it now through telescopes from Earth, the comet appears near the sun. It will be visible through professional telescopes for months to come.
The comet is heading toward our sun and is now 418 million kilometers away. It will get closer to Earth, 305 million kilometers, on December 8.
“The current speed of the comet is high, approximately 149,669 km/h, which is well above the typical speeds of objects orbiting the Sun at that distance,” Farnocchia said. “The high speed indicates not only that the object probably originated outside of our solar system, but that it will also leave and return to interstellar space.
The object was designated as a comet because it appears blurry. Comets tend to look blurry because they are frozen and release dust and particles as they warm up as they approach the sun.
Oumuamua only had one quick visit with us in 2017. The stay of this comet should be a little longer.
“The object will reach its maximum brightness in mid-December and will remain observable with moderate-size telescopes until April 2020,” Farnocchia said. “After that, it will only be observable with larger professional telescopes until October 2020.
Future observations will shed more light on its size, rotation and trajectory.