Giant Star Betelgeuse Gains a Companion express
Betelgeuse is a giant star ready to explode as a supernova. But it may not be alone: a small companion star, Sivarkha, circles in a tight orbit. Every 2000 days, it plunges through Betelgeuse’s outer layers, like a boat cutting through water, leaving waves of superheated gas.
Astronomers spotted this by breaking Betelgeuse’s light into colors — the method of spectroscopy reveals the subtlest motions of matter. The star's flickering, which puzzled scientists, is now explained. Remarkably, though Betelgeuse would stretch from the Sun to Jupiter’s orbit, its outer shell is cooler than our star’s surface. That lets the companion survive each close pass. Watching this cosmic dance brings us closer to understanding the final fate of massive stars.
Original abstract
as written by the authors arXiv:2601.00470v1
Recent analyses conclude that Betelgeuse, a red supergiant star (HD 39801), likely has a companion object with a period of about 2000 days orbiting at only 2.3 stellar radii, deep in the chromosphere of the supergiant. A probable detection of such a companion, named Siwarha, has just occurred from speckle imaging. This study finds that Betelgeuse spectra in the optical region and ultraviolet exhibit signatures of variable circumstellar absorption and chromospheric outflows. These variations are consistent with the ~ 2000-day period of the companion object. Circumstellar absorption evident in optical Mn I lines, and mass outflow marked by ultraviolet Fe II, Si I, and Mg I lines increase after the transit of the companion across the disk of Betelgeuse. Following the eclipse of the companion, the absorption and outflow slowly decrease in advance of the next transit. The occurrence and variation of this plasma appear consistent with the presence of a trailing and expanding wake caused by a companion star orbiting within the atmosphere of Betelgeuse.
Betelgeuse is so vast that if you placed its center where the Sun is, its surface would reach the orbit of Jupiter.
In the novel 'The Hitchhiker's Guide to the Galaxy,' one of the planets orbits Betelgeuse.