Although scientists had long hypothesized the existence of interstellar vagabonds, objects that are not tied to any star system and that roam the cosmos , tracking them is still quite an arduous task.
On October 19, 2017, the first detected interstellar object flew past Earth on its way out of the solar system. Less than two years later, in 2019, an amateur astronomer detected a second object, an easily identifiable interstellar comet designated 2I / Borisov. But is the visit of an interstellar object as rare as we think? The appearance of these two objects verified previous theoretical work that concluded that interstellar objects (ISO) regularly enter our solar system. Is that so?
How many visit us each year?
According to a new study led by researchers from the Interstellar Studies Initiative (i4is, a nonprofit organization dedicated to conducting interstellar flights in the very near future), approximately seven interstellar visitors approach Earth each year and follow orbits. predictable while they are in our solar system, which would make it possible for us to send a spacecraft to meet one of them in the near future. Hence we can conclude that it is not so strange that we have visits of interstellar objects regularly.
“Just by proving that they exist, it has had a profound impact, creating a field of study almost out of nowhere. Interstellar objects offer us the opportunity to study, and in the future, literally touch exobodies, decades before the first possible missions even to the closest stars, such as Proxima Centauri, “the authors explain in their study, which is being peer-reviewed.
Regarding the first alien wanderer, Oumuamua , his discovery led scientists to hypothesize that ISOs are common space tourists . During its approach to the sun, observations made by the Hubble Space Telescope revealed that the object was moving faster than anticipated as it moved towards the edge of the solar system. And while several theories arose around Oumuamua, including the possibility that it was an alien spacecraft, its peculiar acceleration was primarily attributed to the phenomenon called degassing. When a cosmic object passes close to the Sun, it heats up and begins to release gases, this, in turn, causes an acceleration in the speed of the object.
Since the ISOs were formed in another star system, the opportunity to study them closely would offer scientists an idea of the conditions present there. In fact, studying interstellar travelers is the best alternative to sending interstellar probes to neighboring star systems. Of course, any mission of this type involves many technical challenges.
Method
The scientists used data from the local velocity distribution of stars and employed a standard gravitational approach model to predict velocity-dependent ISO flux , concluding that, in an average year, approximately seven objects similar to Asteroids can visit the solar system, while comet-like objects, such as 2I / Borisov, would make a very rare guest appearance once in 10 to 20 years.
According to his calculations, “∼92 of the incoming ISOs will be residents of the galactic thin disk, ∼4 per decade will be from the thick disk, ∼1 per decade will be from the halo and at most ∼3 per century will be loose objects, ejected from our galaxy or entering the Milky Way from another galaxy ”.
Referencia: Interstellar Objects in the Solar System: 1. Isotropic Kinematics from the Gaia Early Data Release 3. arxiv.org/abs/2103.03289 arXiv:2103.03289v1 [astro-ph.EP]
