The solar system’s first interstellar visitor, first spotted Oct. 19, to the delight of astronomers, has been found to be an unusual, elongated, red-colored, and cigar-shaped asteroid.
Oumuamua! It Is An Interstellar Visitor
The interstellar interloper, which originated elsewhere in the Milky Way, has been named Oumuamua by its discoverers after the Hawaiian word for “a messenger from afar arriving first.” It was first referred to as A/2017 U1 and is now also known as 1I/2017 U1.
The color, brightness, and orbit of the object were measured with the help of the European Southern Observatory’s Very Large Telescope in Chile and other ground-based telescopes.
New data revealed that the interstellar asteroid has a highly-elongated shape and it is 10 times as long as it is wide. The aspect ratio is greater than what astronomers have observed for any comet or asteroid in the solar system to date.
The same holds true for its brightness, which varies by a factor of ten. It is a characteristic unknown in comets and asteroids that originate in the solar system because none of them vary so widely in brightness with such a large ratio between length and width. The elongated asteroid may provide more insight into how other star systems formed, according to NASA scientists.
“For decades we’ve theorized that such interstellar objects are out there, and now – for the first time – we have direct evidence they exist,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “This history-making discovery is opening a new window to study formation of solar systems beyond our own.”
The research team from NASA, who published their findings in the Nov. 20 issue of the journal Nature, has said that the reddish hue of the asteroid indicates that it is a dense object that comprises of rock and metals. It has no ice or water and the impact of irradiations from cosmic rays for more than hundreds of millions of years has reddened its surface.
The Lone Wanderer
The scientists have suggested that the cigar-shaped asteroid has been traveling through the Milky Way, unattached to any other star, for hundreds of millions of years before entering the solar system.
Oumuamua was found to be traveling at a speed of about 38.3 kilometers per second as of Nov. 20. Its last known location was approximately 200 million kilometers from Earth. The asteroid passed Mars’s orbit around Nov. 1 and will pass Jupiter’s orbit in May of 2018. It will wander beyond Saturn’s orbit in January 2019.
The interstellar interloper will make its way for the constellation Pegasus, as it leaves the solar system and NASA will continue to study Oumuamua until it does so.