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Viewings: 4372Weakly glowing stars to form a very significant part of the stellar population. Among them are those, around which revolve they own planet. But still, it is unclear whether they naturally or were captured from the outside? A new study by astronomers slightly open a veil of mystery above the old mystery.
In order "see" brown dwarfs, you need to register radiation in the infrared range, because they radiate heat. The study and classification of such stars started in 1995, when it was first confirmed by the real existence of the brown dwarf, and currently astronomers believe that these stars in our milky way galaxy are the most numerous! The first hundred light brown already sufficiently studied, and the next "catch" must be huge.
Brown dwarfs may be a single star, or to enter into dual or multiple systems. The weight of this type of light is small, but in tens of times the mass of Jupiter, the upper estimate limit is considered to be 80 mass of the giant of the Solar system. A curious feature is the radius of brown dwarfs, equal to the radius of our Jupiter, although mass can vary within a wide range - this is the physics of these objects. They need to be distinguished from exoplanets, which also can be very similar to the data of the star.
Systematics and identification of brown dwarfs is rather intricate and complex, but among them there are such, around which revolve they own planet. But still, it is unclear whether they naturally or were captured from the outside? This is very interesting, because brown dwarfs are very numerous, and planets in them - in the case of natural formation - must be abysmal!
Therefore it is interesting to work in a coordinated project (Atacama Large Millimeter / submillimeter Array, ALMA) European space Observatory, which combines radio telescopes operating in the millimeter and submillimeter range. The study dust accretion disk around a brown dwarf revealed a striking feature: disc contained a rather large particles, solid mm grain size.
Previously, these particles were met only in dense protoplanetary disks around the emerging stars. Therefore, it is necessary to reconsider the theory of the formation of rocky planets of the earth type. Especially important can be a lot of them in a regular occurrence in the systems of brown dwarfs.
The object causing the sensation of a young brown dwarf in the field of formation of stars in the constellation Ophiuchus, it bears the name of Ro Ophiuchus 102, the album was "granular", not fine dust formation. When the mass of this brown dwarf is about sixty jupiterians masses in its bowels can't burn sustained thermonuclear reaction, as is the case with the more massive the shining of stars similar to the Sun.
But, nevertheless, he powerfully radiates warmth, that is glows in the infrared, well, if to consider, that the gravitation compresses the star, and the convection boiling and mixes heated substance of the brown dwarf, which can emit a faint reddish glow in visible range, it turns out that if revolve around the planet, they will receive a sufficient quantity of heat!
To the question about the origin of the protoplanetary objects of planetesimals always offered one answer: if dust particles grow to a millimeter in size, further consolidation is predetermined. It becomes the determining factor, causing further transformed Association of matter in the body of the planets. So is there such planet Earth: from accidental collisions proto in the disk formed around a star. Microscopic particles of matter protoplanetary disk collide and stick together, they look like very fine sand or soot.
Regarding the development of planetbossi processes in brown dwarfs - skepticism astronomers was very strong. Disks around the stars, as I thought specialists, very sparse, respectively substances around low-mass dwarfs should be less than around much larger conventional bodies. Quick movement of the particles in the weak gravitational effects is not conducive to stick together. It followed the assumption that the emergence of the planets around the black dwarfs probably impossible, moreover, that accidentally created a larger particles under the action of gravity rush to its centre, Utaka from the external parts of dust disk where they can be found.
Only modern technical possibilities of the ALMA project has revealed the true state of Affairs. Group of radio telescopes have allowed to achieve in the conditions of ground-based observations of a strong increase sensitivity to radiation with a wavelength of the order of a millimeter. This radiation is generated by the substance disk is heated by radiation from the brown dwarf. The explanation of the results is that usually the dust particles disk practically does not emit energy in the waves, the length of which is more than the size of the particles.
While on the waves, slightly exceeding the sizes of particles, usually there are noticeable and the sharp drop in brightness. In the conducted experiment comparing the brightness of the disk at wavelengths of 0.89 mm and 3,20 mm was not detected a sharp jump brightness, which was to be manifested. This may be evidence of a certain number of dust particles in the disk with the sizes of the order of millimeters or more.
Leading specialist Luca Ricci (Luca Ricci) from the California Institute of technology (USA) comments on the results: "For us it was a complete surprise to discover mm grain size in such a delicate and ephemeral dust disk, solid dust particles of this size, generally speaking, should not be formed in the cold outer regions of the disk around a brown dwarf, but I think it's still happening. We do not know whether there to form a rocky planet, but we can see the certain steps in this direction, we have to change our ideas about the conditions under which the size of solid formations can start to grow".
Another result is obtained due to the high permission in a group of telescopes ALMA: in the vicinity of brown dwarfs have been found, the characteristics, carbon monoxide. This is the first case of registration of cold molecular gas in the disk around the star of this type. Previously carbon monoxide found only in the disk of young stars, like dust grains millimeter in size, indicating possible generality of processes around these different stars!
It should be noted that the total mass accretion disk around Ro Ophiuchus 102 is by calculations about 0.3-1 percent of the mass of the brown dwarf, and the diameter is about 40. that is, All of these parameters correspond to the parameters of normal stars with small weight. So maybe around this star really exist planets similar to ours. Well, and if so, it is not excluded that they are somebody inhabits...
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