On October 19, 2017, the Pan-STARRS telescope at Haleakala Observatory in Hawaii detected what looked like a small comet moving at high speed about 33 million kilometers from Earth. However, this space rock exhibited some truly unusual characteristics. There was no trace of the typical tail exhibited by comets, but it seemed to have ice inside and its composition was reminiscent of both that of metallic asteroids and that of some objects located at the limits of our planetary system. Like them, it contains chemical substances called tholins that appear when some organic molecules, such as methane, are irradiated by cosmic rays.
Oumuamua, as it was baptized, showed a chaotic and non-periodic rotation, perhaps as a result of an impact with an object, such as a planet in formation, according to a published study by the School of Mathematics and Physics of the Queen’s University of Belfast. in the journal Nature Astronomy . In addition, it had a very peculiar shape, extremely elongated – there are different estimates of its size, ranging between 230 and 400 meters in length and between 35 and 40 in width – and it was moving so fast that, according to astronomers, it was impossible that it had originated in the solar system: it was, therefore, the first space rock detected that came from interstellar space . In fact, it couldn’t get caught in a solar orbit either, so it would end up leaving our galactic neighborhood.
Tirachinas espacial
Now, a new work coordinated by Alan Jackson, from the Center for Planetary Sciences at the University of Toronto, in Scarborough (Canada), points out that, most likely, it could come from a binary star system , presided over by two stars. In their essay, published in the Monthly Notices of the Royal Astronomical Society , Jackson and his collaborators indicate that this type of double system usually ejects rocky objects, similar to Oumuamua; at least, much more usually than others where ice is more abundant, as happens with comets. And since binary systems are quite common, your hypothesis is that this space visitor comes from one of them.
From the available data, they have concluded that it should have formed in a relatively hot star system with a high mass, since these types of objects are more likely to occur. The researchers also suggest that this asteroid was probably ejected from its system at some point during the formation of the planets. Oumuamua’s orbit also points in that direction. “This has the largest eccentricity ever observed in a body that has passed through our solar system,” says Jackson.
Reference: Ejection of rocky and icy material from binary star systems: Implications for the origin and composition of 1I / ‘Oumuamua. Alan P Jackson et al. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnrasl/sly033
Image: ESO / M. Kornmesser
