Movatterモバイル変換

Explanation:Looking for that perfect holiday gift for an astronomer?Consider this "star in a box".Of course, the box is actually a computational box consistingof a three dimensional grid of points, and the staris a virtual one whosephysicalproperties and internaldynamicsare numerically simulated at the points on the grid.While computers and software capable of a totally realistic numericalsimulation of a complete star don't presently exist,researchers have been making progress.This picture isa movie frame from a recentnumerical simulation of asupergiant star withproperties intended to approximate the real starBetelgeuse.The single frame shows large convection cells and brightspots mottling the virtual supergiant's surface.Simulation moviesshow these surface features changingsubstantially with time.Encouragingly,telescopicobservations indicate that thesurface of Betelgeuse does indeed have prominent large scalefeatures and thewell-known star'sbrightness variations are detectable with the unaided eye.The real supergiantBetelgeuse is some 2,500 degreescooler than, and 620 times the size of the Sun.