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NASA learns more about Interstellar Visitor Oumuamua, the first known interstellar object to visit our solar system |

<! – -> By NASA // November 17, 2018 <! – -> In 2017, NASA's Spitzer Space Telescope discovered the…

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By NASA // November 17, 2018

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In 2017, NASA’s Spitzer Space Telescope discovered the object called “Oumuamua

In November 2017, researchers pointed to NASA’s Spitzer Space Telescope against the object” Oumuamua – the first known interstellar object to visit our solar system. The infrared Spitzer was one of many telescopes pointing to “Oumuamua in the weeks after the discovery of October.” (NASA image)

(NASA) – In November 2017, researchers pointed to NASA’s Spitzer Space Telescope against the object “Oumuamua – the first known interstellar the object to visit our solar system. The infrared Spitzer was one of many telescopes that pointed to “Oumuamua in the weeks after the discovery it in October.”

“Oumuamua was too weak for Spitzer to detect when it saw more than two months after the object’s closest approach to the ground in early September. However,” non-discovery “sets a new limit to what the strange object may be. 19659009] The results are reported in a new study published today in the Astronomical Journal and co-author of researchers at NASA’s Jet Propulsion Laboratory in Pasadena, California.

The new size limit is consistent with the results of a research paper published earlier this year, which suggested that gasification was responsible for the small changes in Oumuamuas speed and direction as tracked last year: The authors of the paper concluded that the expelled gas acted as a small propeller that carefully printed the object.

This determination was dependent on “Oumuamua is relatively smaller than common solar system comets. (The conclusion that “Oumuamua experienced degassing suggested it was composed of frozen gases, similar to comets.)

” “Oumuamua has been full of surprises from day one so we were eager to see what Spitzer could show” said David Vibration, leading author of the new study and a professor of astronomy at Northern Arizona University. “The fact that” Oumuamua was too small for Spitzer to detect is actually a very valuable result. “

” Oumuamua was first discovered by the University of Hawaii Pan-STARRS 1 telescope at Haleakala, Hawaii (the name of the object is a Hawaiian word meaning “visitor from the greatest arrival first”), in October 2017 while the telescope examined for proximity to asteroids near the earth.

Researchers have concluded that ventilation surfaces on the surface of “Oumuamua must have released gas jets, giving the object a Slight increase in speed, which researchers discovered by measuring the object’s position as it passed through the Earth in 2017.” (NASA image) [19659015] Subsequent detailed observations made by several terrestrial telescopes and NASA’s Hubble Space Telescope discovered the solar beam reflected by the Oumuamuas surface. Large variations in the brightness of the object suggested that “Oumuamua is very elongated and probably less than half a mile (2,600 feet or 800 meters) in its longest dimension.

But Spitzer traces asteroids and comets using infrared energy or heat that radiate, which can give more specific information about an object’s size than optical observations of reflected sunlight alone.

That Oumuamua was too weak for Spitzer to discover sets a limit on the total area of ​​the object. Because non-detection can not be used to assume form, the size limits are presented as “Oumuamuas diameter would be if it was spherical.”

Using three separate models that give slightly different assumptions about the composition of the object, Spitzer’s non-detection limited “Oumuamuas” spherical diameter to 1.440 meters, 460 feet (140 meters) or maybe as little as 320 meters (100 meters). The wide range of results derives from the assumptions about “Oumuamuas composition, which affects how visible (or weak) it seems that Spitzer was a certain size.

Small but Reflective

The new study also suggests that “Oumuamua can be up to 10 times more reflective than the comet found in our solar system – a surprising result, according to the paper authors.

Since infrared light is to a large extent heat radiation produced by “hot” objects, it can be used to determine the temperature of a comet or asteroid, in turn, this can be used to determine the reflectivity of the object’s surface – what researchers call albedo. a dark sunlight t-shirt warms up faster than a light, a low reflection object retains more heat than an object with high reflectivity. So a lower temperature means a higher albedo.

A comedian albedo can change throughout its lifetime . As it passes near the sun, a bowl of ice warms and turns directly into a gas, sweeps dust and dirt from the comet and reveals more reflection they are.

“Oumuamua had been traveling through interstellar space for millions of years far from any star that could update its surface. But it may have gotten its surface updated through such an outgassing when it made an extremely close attitude to our Sun, just over five weeks before it was discovered. In addition to sweeping dust and dirt, some of the released gas may have covered the surface of “Oumuamua with a reflective surface and snow – a phenomenon that has also been observed in comets in our solar system.”

“Oumuamua is coming out of our solar system – almost as far from the Sun as Saturn’s path – and far beyond reach of existing telescopes.

“Usually if we get a measurement from a comet that’s so weird, we’ll go back and measure it again until we understand what we see,” says Davide Farnocchia, from the Center for Near Earth Object Studies (CNEOS) at JPL and co-authors on both sides. “But this one is gone forever, we probably know so much about what we’ll ever know.”

JPL manages Spitzer Space Telescope Mission for NASA’s Research Directorate in Washington. Science activities are conducted at the Spitzer Science Center in Caltech, Pasadena, California.

Space operations are based on Lockheed Martin Space Systems Company in Littleton, Colorado. Data archived at Infrared Science Archive hosted by IPAC at Caltech. Caltech manages JPL for NASA.


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