US, WASHINGTON (ORDO NEWS) — Almost all the stars and all previously discovered planets are in the thin disk of the Milky Way. Now, astronomers have found the first exoplanet beyond, and it turned out to be very unusual.
The achievement is described in a scientific article accepted for publication in the Astronomical Journal. In the meantime, you can familiarize yourself with her preprint.
The Milky Way has a complex structure. It looks like a pancake (flat component) immersed in a round bubble (spherical component).
“Damn”, in turn, has two layers. The inner layer is a thin disk. Its thickness is about a thousand light years. It is here that contains most of the stars, including the Sun, and almost all interstellar gas.
The outer layer is a thick disk several thousand light years thick. In addition, in the center of the Galaxy there is a dense sphere of stars and gas (bulge), which extends beyond a thin, but not thick disk.
Mankind today knows more than 4,000 planets . They all lie in a thin disk, which is not surprising.
Firstly, it is there that most of the stars are located. Secondly, the luminaries of the thick disc, as a rule, contain very few elements heavier than helium in comparison with the Sun. According to modern theories, such stars rarely appear in such stars.
Finally, luminaries outside the thin disk are simply too far from Earth, and looking for exoplanets from them is not an easy task for modern telescopes.
And so the TESS orbital observatory helped astronomers make the long-awaited discovery. A planet was discovered in the star LHS 1815. Data on the distance to the star and its speed, obtained by the Gaia space telescope, show that this star is in a thick disk. A thin disk crosses its orbit around the center of the Galaxy, that is, a celestial body periodically dives into it to emerge from the other side.
Now LHS 1815 is located low above the plane of the Galaxy, just 97 light years from Earth. But in its orbital motion, a star from time to time moves away from this plane by 5870 light years.
According to the rules, the discovered exoplanet was designated LHS 1815b. Researchers have already confirmed the discovery with the help of other telescopes, at the same time specifying the “foundling” parameters.
It turned out that LHS 1815 is extremely close to the Earth in size: its radius is 1.088 0.064 Earth. However, it is 4.2 1.5 times more massive than the globe, and this is very strange.
Even based on the lower estimate for mass and the upper for radius, the average density of the planet is equal to 10 grams per cubic centimeter. From the average estimates, we have 18 grams per cubic centimeter.
This is more than twice the density of iron (8 grams per cubic centimeter) and close to the density of uranium (19 grams per cubic centimeter). In other words, LHS 1815b consists of some extremely dense substance.
The planet is so close to its sun that the “year” on it lasts only three earth days. Despite the fact that LHS 1815 is a small and dull red dwarf, such proximity with a luminary hardly leaves this world a chance of habitability.
But even if there are no brothers in mind, a planet discovered in a thick disk is a real gift for scientists.
As long as it is so close to Earth, astronomers can study it with the best telescopes. Perhaps this will help to solve the riddle of its extraordinary density and find out how else this “resident of the outskirts” differs from the planets familiar to researchers.
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