On August 30, 2019, amateur astronomer Gennadiv Borisov detected the first extrasolar comet that we are aware of to date. It was called 2I / Borisov and it was determined that it was traveling at more than 120,000 km / h with a size that would be between 1.4 and 6.6 km. Borisov was the second interstellar object detected in the vicinity of our solar system. The first was the famous asteroid Oumuamua, detected in 2017 and which caused a real stir in the scientific community.
Now, an article published in the Monthly Notices of the Royal Astronomical Society suggests that these interstellar visitors could be much more frequent than we think, but we simply lack the proper technology to detect them. The authors base these conclusions on a series of calculations showing that in the Oort Cloud, a layer of small ice fragments located at the edge of our planetary system, interstellar objects could outnumber those that belong to our solar system. .
“Before the detection of the first interstellar comet, we had no idea how many such objects were in our solar system, but the theory about the formation of planetary systems suggests that there should be fewer visitors than permanent residents,” explains Amir Siraj, a researcher at the Harvard & Smithsonian Center for Astrophysics and author of the work. The calculations were made from the conclusions drawn from Borisov , and contain significant uncertainties, but the authors consider that, even taking them into account, interstellar visitors would prevail over native objects.
Difficult to detect
The aforementioned Oort Cloud is located between 0.03 and 0.75 light years from our Sun, and its objects do not emit their own light, so this ‘debris’ that accumulates in the confines of our solar system is very difficult to detect. The authors recall that asteroids are continually being discovered that are then not analyzed or tracked year after year. “We think they are asteroids, then we lose them without looking at them in detail.” Many of these, in light of the new work, could also be star visitors.
“Interstellar objects in the planetary region of the solar system should be rare, but our results clearly show that, in the dark stretches of the Oort cloud, they are more common than material in the solar system ,” say the authors, who are confident that Next-generation observations help confirm your calculations.
For example, the launch of the Vera C. Rubin Observatory , scheduled for 2022, could help detect many more visitors like Borisov. The Automated Census of Occultations by Trans-Neptunian Objects (TAOS II) , which is specifically designed to detect comets in the outer reaches of our solar system and which are expected to be operational by the end of the year, could help locate some of these passersby.
“The abundance of interstellar objects in the Oort cloud suggests that much more remains of the formation of planetary systems than previously thought,” explained Siraj. “Our findings show that interstellar objects can impose interesting constraints on the formation processes of the planetary system, since their implicit abundance requires a significant mass of material to be expelled in the form of planetesimals, ” says the expert. “Along with observational studies of protoplanetary disks and computational studies of planet formation, the study of interstellar objects could help us uncover the secrets of how ours and other planetary systems formed.”
