Saturday, 20 October, 2018

Astronomers Record First Observation of an Interstellar Object

Theresa Hayes | 27 October, 2017, 20:57

A/2017 U1's slingshot route suggests it is a recent visitor to the solar system - and is now on its way out again.

Assuming it to be a comet, astronomers designated it C/2017 U1, but on 25 October new imaging from the Very Large Telescope in Chile revealed no comet characteristics.

Is the mysterious space object spotted zooming through space a comet? It had also passed under Earth orbit on October 14 at a distance of about 15 million miles (24 million Km), at a distance which is 60 times the distance between Earth and Moon. It appears that the object traveled to the solar system from the direction of the constellation of Lyra, and entered the solar system nearly directly above the plane of orbits of most of the planets.

Whatever it is, NASA is fairly certain it's a unique object. It was first detected by Rob Weryk, an astronomer at the University of Hawaii in Honolulu, and confirmed by the European Space Agency's telescope on Tenerife in the Canary Islands. Normally, comets orbit the sun; this one dove into the plane of our solar system at a almost perpendicular angle, swooped around the sun at 57,600 miles per hour, and headed back out into space. Even comets, which come from a distant reservoir of icy rocks in the solar system called the Oort cloud and can have highly titled orbits, still orbit the sun. It has now shot back up above the plane of the planets and, travelling at 27 miles per second (44 kilometers per second) with respect to the Sun, the object is speeding toward the constellation Pegasus.

Scientists worldwide are turning their telescopes toward the object, hoping observations of it as it leaves the solar system will shed light on its origin and composition.

Experts estimate the object is about 160 metres (525 feet) across, reports Kelly Beatty at Sky & Telescope, but there's still a lot we don't know for sure about A/2017 U1, starting with - where did it come from? "We can say with confidence that this object is on its way out of the solar system and not coming back".

Based on its current trajectory, the visitor came from the constellation Lyra and approached our solar from "above", perpendicular to the plane that most planets orbit the sun.

A/2017 U1 crossed under the ecliptic plane just inside of the Mercury's orbit on September 2.

"What's most surprising is that we've never seen interstellar objects pass through before", she said.

Because this is the first object of its type ever discovered, rules for naming this type of object will need to be established by the International Astronomical Union.

"We have been waiting for this day for decades", said Paul Chodas, manager of NASA's Center for Near-Earth Object Studies.

Long theorized to exist, such objects are likely material ejected from planetary systems during their planet formation processes, noted Karen Meech, an IfA astronomer who studies small objects and their connection to the formation of solar systems.