The way hungry young stars suck in food keeps most X-rays in, too
Lab re-creation of feeding process will help better calculate how fast stars grow
HOW DOES YOUR STAR GROW? Young stars are surrounded by disks of dust and gas that will eventually form planets, as shown in this artist’s illustration. But first, the stars suck material out of the disk via columns shaped by magnetic fields.
L. Calçada/ESO
A plasma cocoon lets growing stars keep their X-rays to themselves. Laboratory experiments that mimic maturing stars show that streams of plasma splash off a star’s surface, forming a varnish that keeps certain kinds of radiation inside.
That coating could explain a puzzling mismatch between X-ray and ultraviolet observations of growing stars, report physicist Julien Fuchs of École Polytechnique in Paris and colleagues November 1 in Science Advances.
Physicists think stars that are less than 10 million years old grow up by drawing matter onto their surfaces from an orbiting disk of dust and gas. Magnetic fields shape the incoming matter into columns of hot, charged plasma. The same disk will eventually form planets (SN Online: 11/6/14), so knowing
