An Interstellar Object
https://twitter.com/popsci/status/924059387295084547
December 4, 2017
For the first time ever, an unidentified object, from interstellar space, has been spotted in our solar system. The unidentified object was named A/2017 U1. Paul Chodas, a manager of the center for Near-Earth Object Studies at NASA, says that, “so far, everything indicates this is likely an interstellar object, but more data would help confirm it.” Researchers base this preliminary conclusion on A/2017 U1’s hyperbolic orbit. “It was obvious that the object has a hyperbolic orbit, “ Dr. Farnocchia said, this means that its trajectory is open-ended rather than elliptical, like objects in our solar system. This shows that it came from outside our solar system and will leave the system. A hyperbolic orbit is shown through the path that A/2017 U1 takes through the middle of our solar system. Other hyperbolic objects have been spotted before, but they were nudged onto escape trajectories by gravitational interactions with planets, said Matthew Holman, director of the Minor Planet Center in Cambridge, Massachusetts. “All other plausible solutions don’t work out”, Holman told space.com, “so you’re left with, this thing came from elsewhere.”
On October 19, Dr. Weryk, an astronomer at the University of Hawaii Institute for Astronomy, was reviewing the images that were previously captured by the universities Pan-STARRS 1 telescope on the island of Maui when he came across the object. At first Dr. Weryk thought it was some sort of space rocket, known as a near earth object, but he quickly realized its motion made no sense. The object was much faster than any asteroid or comet, and he quickly realized it was not from this solar system. “Its moving so fast that the sun can’t capture it into an orbit,” Dr. Weryk said. “We’ve never seen anything like this before,” said Rob Weryk. “We are just scrambling right now to secure big telescope time, prepare our observations, and download the data,” said Karen Meech, an astronomer at the University of Hawaii Institute for Astronomy. Dr. Meech noted that scientists did not have much warning about this object when it came into the solar system because it was blocked by the brightness of the sun. When the object was first spotted it was thought to be a comet (and was therefore first given the name C/2017 U1) Although, observations have revealed no evidence of a coma (the fuzzy cloud of gas and dust surrounding a comet’s core). Holman said that he suspects that A/2017 U1 is more ice than rock, and is made from the stuff that forms relatively far from stars, and is most likely to be booted out of solar systems into interstellar space, which tends to be ice-dominated. Although, comets don’t always display comas; these features develop when the icy wanderers get close enough to the sun for material to boil off into space. Although the object came from outside of our solar system, it may be made up of completely different material than the asteroids and comets that we have studied. Astronomer have predicted this occurrence, but this is the first time that is has been recorded.
Astronomers, such as Dr. Farnocchia, have reconstructed A/2017 U1’s path through our solar system, using their knowledge of the object’s orbit. A/2017 U1 approached from the direction of the constellation Lyra, traveling through space at nearly 57,000 miles per hour, and it is thought to be less than 1,300 feet wide. The object came in nearly perpendicular to the ecliptic, the plane in which our eight planets orbit. On September 2nd, the object crossed over Mercury’s orbit. On September 9th, the object came its closest to the sun, at a distance of about 23 million miles. The object received a boost from the star’s gravity, and it sped past at about 55 miles per second. On October 14th, the object came its closest to earth. The object came within 15 million miles of Earth at about 37 miles per second. The object then traveled above the ecliptic and was speeding towards the outer solar system at about 97,200 miles per hour. The object was heading out of our solar system towards the constellation Pegasus. “How many of these are flying through interstellar space?” Holman said. “And then the next thing will be, how do we find more of them?”
Sources:
https://www.space.com/38580-interstellar-object-spotted-comet-asteroid-mystery.html
https://www.nytimes.com/2017/10/27/science/interstellar-object-solar-system.html
