Astronomers have used the Spitzer Space Telescope, 250 million kilometers from Earth, to define the infrared emission of the interstellar asteroid 'Oumuamua and estimate its size.
Astronomers at CfA (Harvard-Smithsonian Center for Astrophysics) Joe Hora, Howard Smith and Giovanni Fazio, along with their team of scientists from the Office of Near Earth Objects at NASA and other colleagues, pointed the IRAC camera at the site where the predictions placed 'Oumuamua. As it is not linked to the solar system and moves at great speed, the path of Oumuamua in heaven is comparatively difficult to calculate.
After thirty hours of observation, a relatively long time, the object was not detected, although later orbital analyzes confirmed that the camera was pointing correctly towards the object, that It has an elongated shape. Given the distance it is located, Spizer has a very different angle of vision towards' Oumuamua than Earth's telescopes.
The limit for its emission, however, was so low that it allowed the team to restrict some of its physical properties. The lack of an infrared signal, for example, suggests that it has no gas or dust, which would be expected if it were a body similar to a comet.
Scientists also calculate that, depending on their exact composition and reflectivity, 'Oumuamua has at least 240 meters, and maybe up to a kilometer, of maximum length.
The object has now been placed too far for any space telescope to see. Although it will remain an interstellar mystery, it reminds us once again that our cosmic neighborhood is full of surprises, the Smithsonian Astrophysical Observatory said in a statement.