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In 2017, astronomers and the entire world were surprised to learn that an interstellar object (called "Oumuamua") was passing on Earth to get to the outer solar system. After conducting many surveys, scientists wondered how this object was. What speculation, whether it's a comet or an asteroid, a comet fragment or even an extraterrestrial solar sail!
But one of the main lessons of this event was the discovery that such objects regularly cross our solar system (and some remain there). And it turns out that astronomers from NASA, ESA and the International Scientific Optical Network (ISON) have announced the detection of what could be a second interstellar object! Could this be 'Oumuamua 2.0? And if so, what mysteries could he present?
The new object was designated C / 2019 Q4 (Borisov) in honor of Gennady Borisov, astronomer of the Crimean Astrophysical Observatory, who detected the object for the first time August 30th. NASA's Scout system, which monitors asteroids and comets recently discovered in the Center for Near-Earth Objects (CNEOS), said it had an unusual orbit shortly after.
A few days later, the famous astronomer Marco Micheli – NEOCC – managed to obtain images of the object through ISON. Micheli, to whom the discovery of several NEOs was discovered, also made several measurements of the position of the object using data provided by the Canada-France-Hawaii Telescope (CHFT) in Manua Kea, Hawaii.
ESA is currently analyzing all available data and planning more observations to get a better idea of the path of the object and its origin. But given its eccentricity, it seems likely that this object could be an interstellar visitor, although this remains conclusive. As Micheli explained:
"We are now working to obtain more observations of this unusual object. We must wait a few days to understand its origin with observations that will either prove the current thesis that it is interstellar, or may change our understanding radically.. "
At this stage, C / 2019 Q4 is known to be a relatively large and active comet, measuring a few km in diameter. It is expected to be closest to the Sun in early December, reaching a distance of about 300 million km, a little more than double the distance between the Earth and the Sun (2 AU). This distance will place it out of the orbit of Mars and therefore does not correspond to the definition of an object close to Earth (NEO).
Assuming that C / 2019 Q4 is a comet, it will start degassing as soon as it reaches the nearest point of its path around our Sun. This will be caused by temperature increases on its surface, resulting in sublimation and release of frozen volatiles (water, carbon dioxide, methane, ammonia). Astronomers will be able to confirm that the object is actually a comet based on the resulting halo (or "tail").
As we know that comets remain stable up to a distance of about 3 AU (448.8 million km) from the Sun, it is fair to say that the fourth quarter of C / 2019 should experience a degassing . It is here that 'Oumuamua began to confuse the scientists, who knew no degassing despite a distance of 38.1 million km from the Sun.
Nevertheless, he managed to accelerate out of the solar system, which was consistent with the behavior of a comet. This has led some scientists to consider that "Oumuamua could actually be an artificial object, or at least a celestial object, that the human being had never met before. This is what makes interstellar objects such a price.
It is no wonder that scientists are so excited that another interstellar object seems to have entered our solar system. This is also the reason why many are looking for low cost and fast deployment concepts for spacecraft, able to meet and explore these objects. If only the fourth quarter of 2019 arrived in our solar system in a few years, ESA's Comet Interceptor mission could do it.
This mission is part of the Cosmic Vision program, ESA's long-term vision for space exploration, which includes "fast-class" missions that can meet transient phenomena (such as comets). The Comet Interceptor proposal (inspired by Oumuamua) envisions three spacecraft that will be the first to visit a comet or an interstellar object as it begins to make its way to the inner solar system.
Whatever the case may be, if other observations show that the C / 2019 Q4 is indeed of interstellar origin, it means that our solar system has been visited by at least two of these objects as long as d & # 39; years. This would indicate that these organizations are much more common than expected, which also means that we will have many opportunities to study them in the future!
Further reading: ESA
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