Star LAMOST J040643.69+542347.8 is located in the outer arm of the milky Way at a distance of about 30 thousand light years from the Sun, and its upper layers are rotated with the record-high rate — approximately 540 kilometers per second, which is 100 kilometers per second faster than the previous record HD 191423. The results of the spectroscopic observations, which allowed to draw this conclusion, writes astrophysicist Guang-Wei Li (Guang-Wei Li) in the paper on arXiv.org.
Stars rotate around its axis from the moment of birth — as the collapse of a gas cloud into a protostar angular momentum is preserved, which leads to a fast rotation. Gradually, the rotation is slowed down by the interaction between the magnetic field of the star with the stellar wind, blowing away the ground. For example, a point on the equator of the Sun moves at a speed slightly more than two kilometers per second. However, there are stars that rotate extremely quickly — the fastest known to date 285 VFTS and VFTS 102 in the Large Magellanic cloud rotates at a speed of 610 kilometers per second. In our Galaxy, until recently, the record speed owned HD 191423 — 435 kilometres per second. The actual speed of rotation of these stars may be even more — because we can only measure the velocity projected on the line of sight.
Solitary star can make spinning difficult, usually rapidly rotating stars are in binary systems and required high speed to its affiliates that actively share stuff. They can be the source of this interesting phenomena, such as long gamma-ray bursts. In addition, the rapid rotation dramatically affects the circulation of matter inside the star. It is mixed the hydrogen is transferred to the nucleus, and the products of the carbon-nitrogen-oxygen cycle to the surface, which increases the lifetime of a star and its luminosity.
Guang-Wei Li (Guang-Wei Li) calls the opening of the most rapidly rotating stars in the Galaxy a happy accident — it was made in the search process using spectroscopic telescope LAMOST stars of class O is the hottest blue stars with the emission lines of hydrogen. Spectral class LAMOST J040643.69+542347.8 was identified as A6.5. Unusually broad lines in the spectrum pointed to the rapid rotation of the star: the fact that we are approaching the edge of the star all the spectrum lines are shifted into the blue part of the spectrum, from receding in the red, and the result of the addition of the spectral lines become wider, the faster the rotation of the star. For reliable measurement of rotational speed, the author used the absorption line of ionized helium He II λ4542 — it is formed deep in the photosphere and stellar wind, it has no effect. It turned out that the speed of rotation of the upper layers of the star projected on the line of sight approximately equal to 540 kilometers per second, which is 100 kilometers per second faster than that found in 2001 HD 191423.