VLA and ALMA observations point to companion disturbing Betelgeuse's atmosphere

Astronomers using the VLA and ALMA found that Betelgeuse's atmosphere periodically becomes egg-shaped, consistent with disturbance from a close companion, Siwarha. The roughly 5.9-year distortion cycle matches a second pattern of brightness variability in the star.

• Betelgeuse is 14 times the Sun's mass and over 640 times its diameter
• Companion Siwarha orbits within three stellar radii, inside the outer atmosphere
• The ~5.9-year distortion cycle matches brightness variations
• Data came from VLA and ALMA radio observations