Asteroids

The interstellar asteroid 'Oumuamua seen by the William Herschel Telescope at La Palma (Image courtesy A. Fitzsimmons, QUB/Isaac Newton Group, La Palma)

An article published in the journal “Nature Astronomy” describes the results of a spectroscopic analysis and thermal modeling of the interstellar asteroid 1I/2017 U1 ‘Oumuamua. A team of astronomers led by Professor Alan Fitzsimmons and Dr. Michele Bannister from the School of Mathematics and Physics at Queen’s University Belfast concluded that, due to its exposure to cosmic rays, a superficial layering of organic and insulating materials occurred on the asteroid and it might contain ice.

Artist's impression of interstellar asteroid 'Oumuamua (Image ESO/M. Kornmesser)

An article published in the journal “Nature” describes the observations carried out on ‘Oumuamua, the named given to the interstellar asteroid whose discovery was announced only a few weeks ago. It was designated as A/2017 U1 but after the creation of a new class of objects for interstellar asteroids its designation was modified into 1I/2017 U1. Observations with ESO’s VLT (Very Large Telescope) and other telescopes showed that it’s likely dense, rocky, reddish and with a very elongated shape.

A/2017 U1's trajectory through the solar system (Image NASA/JPL-Caltech)

The announcement of the discovery of a possible asteroid coming from another solar system is a big deal. Named as A/2017 U1, it was detected on October 19 by the Pan-STARRS 1 telescope in Hawaii, part of a sky observation system normally used to detect celestial bodies of various kinds. Its motion seems incompatible with the trajectories of asteroids and comets gravitationally bound to the Sun so it could be the first celestial body discovered that came from another star, perhaps Vega.

Artist’s concept of 2014 MU69 as a pair of asteroids (Image NASA/JHUAPL/SwRI/Alex Parker)

NASA has communicated the results of the observations of 2014 MU69, the object in the Kuiper Belt that represents the next target for the New Horizons space probe. The study of the observations made on July 17, 2017 when 2014 MU69 passed in front of a star suggests that it has the shape of an extreme prolate spheroid or that it’s actually two asteroids very close if not in contact.