Where did the extrasolar comet ʻOumuamua come from?

This past year, our Solar System had an interstellar visitor. ʻOumuamua, which was discovered in October 2017, was first thought to be an asteroid. Then it was determined that it had changed its course by itself (and not due to gravitational interaction with the Sun or the planets). Its “propulsion system” is thought to be volatile substances that sublimated during the object’s approach to the Sun – typical behavior for a comet.

But where did this extrasolar comet come from?

Using data from the European Space Agency’s Gaia mission, scientists identified a total of 28 possible stars that ʻOumuamua might have once called home. A million years ago, the comet came relatively close to the dwarf star HIP 3757 – the closest approach of any of the candidates, but it was moving at a relatively high velocity. 3.8 million years ago, it was in the vicinity of the Sun-like star HD 292249, where ʻOumuamua had the lowest velocity of all its encounters. A compromise between proximity and velocity is 2MASS J02335086+0144054.
None of the 28 systems, however, has known planets that could have slingshot the comet out of the system.

Researchers are hoping that the next set of Gaia data, which will be a whole order of magnitude richer, will provide some insight. ʻOumuamua’s next appointment, however, is a little clearer: in 716,000 years, the comet will meet TYC 4600-1769-1, but at a high velocity so it will likely fly through this system too.

This artist’s impression shows the first interstellar asteroid: `Oumuamua. This unique object was discovered on 19 October 2017 by the Pan-STARRS 1 telescope in Hawai`i. Subsequent observations from ESO’s Very Large Telescope in Chile and other observatories around the world show that it was travelling through space for millions of years before its chance encounter with our star system. `Oumuamua seems to be a dark red highly-elongated metallic or rocky object, about 400 metres long, and is unlike anything normally found in the Solar System.

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  • BrandonQMorris
  • Brandon Q. Morris es físico y especialista en el espacio. Lleva mucho tiempo preocupado por las cuestiones espaciales, tanto a nivel profesional como privado, y aunque quería ser astronauta, tuvo que quedarse en la Tierra por diversas razones. Le fascina especialmente el "qué pasaría si" y a través de sus libros pretende compartir historias convincentes de ciencia ficción dura que podrían suceder realmente, y que algún día podrían suceder. Morris es autor de varias novelas de ciencia ficción de gran éxito de ventas, como la serie Enceladus.

    Brandon es un orgulloso miembro de la Science Fiction and Fantasy Writers of America y de la Mars Society.