it Was a gigantic star spot cause of the unusual darkening of the star Betelgeuse, which had surprised the beginning of the year, astronomers and the Public? The Thavisha Dharmawardena from the Max-Planck-Institute for astronomy in Heidelberg, and her colleagues in the journal “The Astrophysical Journal Letters reports anyway”. The scientists have evaluated monitoring data from the 700 light-years distant star, which were obtained with the Atacama Pathfinder Experiment (Apex) in Chile and the James Clerk Maxwell Telescope (JCMT) in Hawaii. Both telescopes register the so-called Terahertz radiation, whose wavelength is a thousand times as large as that of the visible light. It is, in particular ends of cool dust in All of it.
In February, the American astronomer Emily Levesque, Philip Massey had hypothesized that one of the old giant star ejected dust cloud was darkening the responsibility of Betelgeuse between February 2019 and February 2020, from ninth on the 25. Ranking of the brightest stars slipping left. At the time, speculation even made it to the round, the star could be on the verge of a spectacular super-Nova explosion – Betelgeuse is 20 solar masses and a far-advanced stage of development is a hot candidate for it. But by the end of February, the star was brighter again and soon reached its normal luminosity. In June, he was because of the Position of the sun from the earth unobservable, however, with the cameras of the space probe “Stereo”, as well as the Mars Rover “Curiosity” were the astronomers of him still in view.
Dharmawardena and your Team to keep the dust hypothesis in the light of the new measurements for non-durable: could be the case, you would have had to be brighter the star in the Terahertz light, in fact, the astronomers noted, also in this spectral range, a decrease in the brightness by 20 percent. Only a cooling of the visible stellar atmosphere could therefore have the star eclipsed; but this is not global, but in a limited area occurred.
blackout by overlapping brightness cycles?
Thus, recordings of the Very Large Telescope of the European southern Observatory had to wait (Eso) have shown that in December 2019 is a half of the visible star surface was darker than the other. “Together with our result, this is a clear indication of huge star-spots, which cover between 50 and 70 percent of the visible surface, and a lower temperature than the brighter photosphere have,” says Peter Scicluna of the Eso and Co-author of the study.
star spots in all the stars. They occur when strong magnetic fields, the hot star matter in the photosphere, so the upper stellar atmosphere, sticking and more cool than the Material in the surrounding atmosphere. However, in a size, as will now be postulated in the case of Betelgeuse, one has observed you have never been. Edward Guinan of the American Villanova University who was not involved in the study, holds a giant star patch for one possible explanation, favoured the idea of a “super granule”: “super-granules are large convection cells in the turbulent outer atmosphere of the giant star. The dough granules at the end Super hot and Shine bright, if they cool down, they become darker and back will eventually sink into the star.“ Guinan points out that Beteigeuzes brightness is known since a long time varies: From the analysis of decades of observations he and his colleague Richard Wasatonic to derive the number of brightness cycles, one of which you suspect that some of the recurring super granules are triggered.
A Superposition of two of these cycles may have led in combination with a particularly dark Minimum of the exceptional darkening. However, an influence of the star dust was still on the table: “in the end, both could be correct: a hybrid model of dust and cooling.”