Discovering new candidates for exosatellations: Is it true?
Artist's understanding of the new exoplanet candidate Kepler 1708-bi. If correct, it's three times smaller than Neptune, the eighth planet in our solar system (about 4 Earth diameters). Image credit: Columbia University, Helena Valencia Wilderström
Satellites are common in our solar system. In fact, there are already more than 200 known moons in our solar system. What about in other star systems? It can be said that the moons of the planets are not only widely distributed in our galaxy, but even outside this range, there are many moons. However, these exoplanets are difficult to detect, and even more difficult to detect than distant planets. There are hundreds of millions of planets orbiting stars in the Milky Way, of which we know more than 4,000 exoplanets. Although not 100% accurate, there are still some ways to detect the existence of exosoluts, for example, exoplanets are generally larger than those in our solar system. This month, Jan. 13, 2022, researchers at Columbia University in New York say they may have found a new way to confirm exoplanets: exostars have orbital radii of more than 5,000 light-years.
In a new peer-reviewed paper published Jan. 13, 2022 in the journal Nature Astronomy, researchers published details of an alien candidate named Kepler-1708 b-i. The data in this information comes from the mission completed by the Kepler telescope.
New exosate candidate: Kepler-1708 b-i
David Gipping and his team at Columbia University's "Cool World Lab" discovered it in the title. Commenting on the difficulty of finding exosolats, he said:
Astronomers have found more than 10,000 candidates for extrasolar planets, but exoplanets are far more challenging. They are "unknown lands".
This could be a candidate for an exomoon orbiting the giant planet Kepler-1708b. The planet is only a little smaller than Jupiter, but it has 4.6 times the mass of the latter. It orbited a star similar to the Sun and traveled 5436 light-years in the opposite direction of Earth over a period of about two years. As expected, larger satellites are more likely to be detected than smaller satellites. Jiping said:
"The first thing that is found in any investigation is often something outlandish. Since our detection sensitivity is limited, the larger they are, the easier it is to detect them. ”
Cold gas giant planets
While studying 70 cold gas giants, researchers discovered the new candidate exoplanet. Like Jupiter and Saturn, their orbits are far away from their stars. At such distances, stars have less traction on any moon, causing them to de-orbit. They only found one signal that might be an exostar, but it was a good one. Ji Ping said: "This is a stubborn signal. We threw away the kitchen sink, but it just wouldn't go. (Moral: We've done our best.) ）
Astronomer David Gipping and his Cool World Laboratory discover new giant exosatellite candidates at Columbia University. Image credit: Columbia University
If planets like Jupiter, Saturn, Uranus, and Neptune have any indications, then that statement seems reasonable: other giant planets should also have moons, and maybe even dozens, like our solar system. We don't have satellites as big as these new candidates for exomosites, but if there are large satellites, then there should also be small satellites.
Some skeptical voices
Unsurprisingly, the news was questioned by some scientists. As Eric Agol, an astronomy professor at the University of Washington, puts it:
This could simply be a fluctuation in the data, or due to the influence of stellar or instrumental noise.
German astronomer Michael Shipck objected:
We find an interesting mysterious object, make predictions, and then decide whether it can be a candidate for exomoon based on future observations. I'd be happy if a second exomosat candidate appeared, but unfortunately only two transits have been observed so far. It would be nice to have more data.
Confirming the existence of the first exomosat would at least be encouraging. Beginning in 1992, the first recorded possible exoplanet was also questioned. Today, out of countless candidates, we confirm that nearly 5,000 of them are exoplanets. As Ji Ping said:
Compared to our parent solar system, these planets are exotic alien species. However, their emergence has led to a better understanding of the formation process of planetary systems.
There are also a small number of other exosatellate candidates. One orbits a planet similar in size to Jupiter, Kepler 1625b. It was declared discovered in 2018. Similar to Kepler-1708 b-i , it also moves farther and farther away from its star as it orbits. If it's really a moon, it's surprisingly large: almost as large as Jupiter! This possible satellite data comes from kepler and Hubble telescopes.
As early as 2014, astronomers announced that there might be a satellite orbiting a stray planet called MOA-2011-BLG-262L and using microlens technology to make a preliminary identification of it. In this case, however, there is still a possibility that the planet is actually a red dwarf and that the moon is a planet.
In 2020, astronomers discovered at least six more exoplanets orbiting exoplanets 200 to 3,000 light-years away.
Summary: Astronomers have announced the discovery of a new candidate for an exomoon orbiting an exoplanet 5,400 light-years from Earth. Data from the Kepler Space Telescope shows that this is the latest, possible exoplanet discovered to date.
Related knowledge
Exomoon or Extrasolar Moon are natural moons that orbit around exoplanets or other non-spherical objects outside the solar system. [2]
Empirical studies of natural moons within the solar system can infer their ubiquity in planetary systems. Most of the exoplanets that have been discovered are giant planets. In the interior of the solar system, giant planets also have many natural moons (moons of Jupiter, moons of Saturn, moons of Uranus, moons of Neptune), so it is reasonable to infer that outer moons are widespread.
Although it is difficult to discover and confirm exoplanets with current technology, through some observation missions, kepler telescopes have discovered many candidate moons, including some possible alien life stars and wandering planets. None of the exoons found so far have been confirmed, and in September 2019, astronomers said that tabby's star, formed by interstellar dust, was observed to be dimming, resulting in the result being disturbed by a single moon.
BY：Paul Scott Anderson
FY：Astronomical volunteer team
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