On October 19, 2017, the first interstellar object detected ever flew over the Earth as it left the Solar System. Less than two years later, a second object was detected, an easily identifiable interstellar comet designated 2I / Borisov.
The appearance of these two objects proved previous theoretical work that concluded that interstellar objects (ISOs) regularly enter our solar system.
The question of how often this happens has been the subject of considerable research since then. According to a new study led by researchers at the Initiative for Interstellar Studies (i4is), approximately seven ISOs enter our solar system each year and follow predictable orbits while they are here.
This research could allow us to send a spacecraft to an appointment with one of these objects in the near future.
The research describing these findings was conducted by several researchers at i4is, a non-profit organization dedicated to conducting interstellar flights in the very near future.
They were accompanied by researchers from the Florida Institute of Technology, the Harvard Institute for Theory and Computing (ITC), the University of Texas at Austin, the Technical University of Munich, and the Paris Observatory.
‘Oumuamua through the William Herschel telescope. (Belfast Queen’s University Telescope / William Herschel)
Oumuamua’s study in October 2017 started a revolution in astronomy and the study of celestial objects. Not only was it an object that had formed in another stellar system, but its arrival and detection involved a large population of these objects.
The detection of 2I / Borisov in 2019 confirmed what many astronomers already suspected: that ISOs are entering our solar system on a fairly regular basis.
In addition to being an i4is physicist (and lead author of the study), Marshall Eubanks is the lead scientist for Space Initiatives Inc. and CEO of Asteroid Initiatives LLC. As he told Universe Today by email, the discovery of Oumuamua and 2I / Borisov is significant in a way that cannot be underestimated:
“[J]proving that they exist, it has had a profound impact, creating a field of study almost out of nowhere (a field that financial authorities are just beginning to recognize). Interstellar objects provide us with the opportunity to study and, in the future, literally touch, exobodies decades before the first possible missions even to the nearest stars, such as Proxima Centauri. “
This led to multiple mission proposals that could meet with future ISOs that were seen going through our system. One such proposal was Project Lyra, which i4is researchers shared in a 2017 study (with support from Asteroid Initiatives LLC).
There is also ESA’s Comet Interceptor mission, which they plan to launch in 2029 to meet with a long-range comet.
“We started working on possible missions to interstellar objects in 2017, right after the discovery of Oumuamua, and initially we focused more on chasing that specific object, in contrast to Seligman and Laughlin, who focused on ISO that could be discovered in the future, ”Eubanks said.
“The Comet Interceptor mission would fall into a similar category (build and wait).”
Given that ISOs were formed in another stellar system, the opportunity to study them closely would give scientists an idea of the conditions that are present. In fact, the study of ISOs is the next best sending of interstellar probes to neighboring stellar systems.
Of course, any such mission involves many technical challenges, not to mention the need for prior notice. As Eubanks explained:
“There are two basic types of missions here: planning and waiting, or launching and waiting, such as ESA Comet Interceptor, and chase missions, such as those needed to reach 1I / ‘Oumuamua. It is very unlikely that any “Chase missions will be able to meet with a retractable ISO; they will almost certainly be limited to fast flyers. Meeting missions, missions to equalize speeds and orbit or land the ISO, will need advance warning.”
To illustrate this, when astronomers first noticed ‘Oumuamua’, it was only after the object had moved closer to the Sun (also known as the perihelion passage) that it made a pass. close to Earth.
Because of this, observers only had 11 days to make observations when they left the solar system and were out of range of their instruments.
Impression of the 2I / Borisov artist beyond our solar system. (S. DagnelloNRAO / NSF / AUI)
In the case of 2I / Borisov, amateur astronomer and telescope maker Gennadiy Borisov saw it on August 30, 2019, about three months before it reached perihelion (December 8, 2019).
But for future missions to meet with them, it is imperative to know as much as possible how often the ISOs arrive and how quickly they travel.
For the sake of their study, Eubanks and colleagues tried to put better restrictions on these two variables. To do this, they began by considering how the speed of an interstellar object is influenced by the local standard of rest (LSR), the average motion of stars, gas, and dust in the Milky Way. the surroundings of the Sun:
“We assume that ISOs come from or form with stars and their planetary systems and that, after being alone, they share the same galactic dynamics as stars. We use the two known ISOs, 1I / ‘Oumuamua and 2I / Borisov., And the efficiency of past and current astronomical surveys to estimate the number of these objects in the galaxy, and stellar speed estimates from the Gaia mission to estimate the speed of propagation we should expect. “
What they found was that, in an average year, the solar system would be visited by up to seven ISO-like asteroids. Meanwhile, objects like 2I / Borisov (quotes) would be rarer, appearing once every 10 to 20 years.
In addition, they found that many of these objects were moving at speeds higher than Oumuamua, which was moving at more than 26 km / s before and after gaining momentum from the Sun.
Knowing these parameters will help scientists prepare for possible ISO encounter missions, something Eubanks and colleagues discussed in more detail in a previous study: “Interstellar Now! Missions to Explore Objects Interstellar Objects.”
As Universe Today reported at the time of its launch, the study addressed a wider range of potential ISOs and the feasibility of reaching them.
Meanwhile, this latest study provides basic information that will support the planning and implementation of these missions. In addition to the Lyra Project and ESA’s interceptor comet, there are numerous spacecraft proposals that could meet with interstellar objects (or even make the interstellar journey themselves).
These include Project Dragonfly, a small spacecraft and laser sail that was the subject of a conceptual design study organized by the Initiative for Interstellar Studies (i4iS) in 2013.
Another is Breakthrough Starshot, a concept proposed by Yuri Milner and Breakthrough Initiatives that also calls for a small spacecraft to be sent to Alpha Centauri using a light candle and a powerful laser array.
This proposal has been articulated in recent years by Professor Abraham Loeb and Professor Manasvi Lingam. While Leob is the founder of the ITC and chairman of the Starshot advisory committee, Lingham is a longtime ITC researcher and co-author of “Interstellar Now!” and the latter document.
In addition to being interstellar, these concepts have been proposed as a possible way to “chase objects” that enter our solar system.
One way or another, we will soon reach the top of other stellar systems. And knowing how to intercept and study the objects that open up to us periodically is a good way to start.
This article was originally published by Universe Today. Read the original article.