NASA has shared some new information about Oumuamua, the mysterious interstellar object that was first spotted by the Pan-STARRS 1 telescope in Hawaii in October 2017.
According to NASA, scientists at the Jet Propulsion Laboratory in Pasadena, California, tried to pick out this space rock using the infrared Spitzer Space Telescope in November last year, but could not spot it with this instrument.
NASA released its information just over a week after a group of scientists published a speculative paper suggesting that Oumuamua could be - but almost certainly wasn't - an extraterrestrial space craft.
Oumuamua is the first known interstellar object ever to enter our solar system from some distant world in the universe. After it was first noticed by Pan-STARRS 1 last year, researchers rushed to gather more information about it, pointing their telescopes in its direction before this weird object disappeared on other side of the solar system.
Oumuamua was first described as a comet, but was later called an asteroid. Finally, it was classified as a new class of interstellar objects never seen before.
Results of initial observations suggested that Oumuamua was highly elongated in shape and less than 800 meters in its longest dimension.
According to NASA, failure to detect Oumuamua through Spitzer puts a limit on the size of this interstellar object. Spitzer telescope tracks comets and asteroids using the infrared energy radiated by these objects, thus enabling scientists to get specific information about their size. Had Oumuamua been too large, it would have been spotted by the infrared telescope.
"Oumuamua has been full of surprises from day one, so we were eager to see what Spitzer might show," said David Trilling, a professor of astronomy at Northern Arizona University and lead author of the new study.
"The fact that Oumuamua was too small for Spitzer to detect is actually a very valuable result."
Assuming Oumuamua to be spherical in shape, scientists tried to estimate its diameter. They used three different models that made different assumptions about the composition of Oumuamua. The results from three models suggested that Oumuamua's spherical diameter will not be more than 440 meters, and could also be as little as 100 meters.
The new results also suggest that Oumuamua may be up to 10 times more reflective than the comets found in our solar system.
The findings of the study are published in the Astronomical Journal.
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