It’s only the second observed “interloper” to cross into our solar system, but interstellar comet 21/Borisov looks incredibly similar to our own comets based on new observations by astronomers. They’re also learning new details about the comet, like the fact that it has a reddish hue, according to a new study.
The Hubble Space Telescope also captured the best view yet of the comet on October 12.
And after detecting the first interstellar object, or object that originated outside of our solar system, known as ‘Oumuamua in 2017, astronomers were better prepared for this one.
Astronomers at Jagiellonian University in Krakow created a computer program called “Interstellar Crusher” after the first observed interstellar object quickly zipped through our solar system.
At the end of August, amateur astronomer Gennady Borisov spotted a new comet while at the MARGO observatory in Crimea. The amateur astronomer used a 0.65-meter telescope he built and saw something that resembled a comet with a short tail.
Observations by NASA’s Jet Propulsion Laboratory Solar System Dynamics Group have supported that this comet has the most hyperbolic orbit out of the thousands of known comets. Orbits help scientists to understand the nature of an object and where it came from.
And on September 8, the Interstellar Crusher software, which scans online data of newly discovered asteroids and comets, issued an alert about the comet. The alert signified that the object may be arriving from interstellar space.
“This code was written specifically for this purpose, and we really hoped to receive this message one day. We only didn’t know when,” said Piotr Guzik, study author at Jagiellonian University.
Since then, observations have confirmed that the comet originated from outside of our solar system and it was named 2I/Borisov by the International Astronomical Union’s Minor Planet Center.
Follow up observations revealed more details about the comet and were published Monday in the journal Nature Astronomy.
“We immediately noticed the familiar coma and tail that were not seen around ‘Oumuamua,” said Michal Drahus, co-author of the study at Jagiellonian University. “This is really cool because it means that our new visitor is one of these mythical and never-before-seen ‘real’ interstellar comets.”
They determined that the comet is dominated by dust, which is typical for comets, and is red in color. It also has a radius just over half a mile. Outside of its hyperbolic orbit, the comet is very similar to those we find in our own solar system.
This lines up with previous early measurements putting the comet at anywhere between 1.2 and 10 miles in diameter, according to Karen Meech at the University of Hawaii.
“Make of this what you will, but based on these initial characteristics, this object appears indistinguishable from the native Solar System comets,” Guzik said.
But astronomers believe the best observations are on the horizon.
“The comet is still emerging from the sun’s morning glare and growing in brightness. It will be observable for several months, which makes us believe that the best is yet to come,” said Waclaw Waniak, co-author at Jagiellonian University.
And we’ll get a chance to know the comet better soon. It’s due to enter the inner part of our solar system on October 26. To look at it right now through telescopes from Earth, the comet appears close to the sun. It will be visible through professional telescopes for months.
The comet is making its way toward our sun and is now 260 million miles away. It will get closest to Earth — 190 million miles — on December 8.
The object was designated as a comet because it appears fuzzy. Comets tend to look fuzzy because they’re icy and release dust and particles as they heat up on approach to the sun.
‘Oumuamua only had a quick visit with us in 2017. This comet’s stay should be a bit longer.
“The object will peak in brightness in mid-December and continue to be observable with moderate-size telescopes until April 2020,” said Dave Farnocchia at NASA’s Jet Propulsion Laboratory. “After that, it will only be observable with larger professional telescopes through October 2020.”
Future observations will shed more light on its size, rotation and path.
“We can safely say that research on this body will be transformative for planetary astronomy and a milestone for astronomy in general,” Guzik said.
Researchers believe that in the future, we can expect to see several large objects that originated outside of our solar system zipping through it. And there could be hundreds of smaller objects passing through each year.