Overview
- A Center for Astrophysics–led team combined Hubble and ground-based observations to track a low-mass companion, Siwarha, disturbing gas inside Betelgeuse’s extended atmosphere.
- Blueshifted Fe II emission is stronger when the companion is in front of Betelgeuse and diminishes after passage as the trailing wake absorbs the signal.
- The wake appears just after each front-side crossing and repeats on a roughly 2,100-day cycle, accounting for the star’s long secondary variability.
- Siwarha is currently obscured by Betelgeuse, and a July 2025 Gemini North ‘Alopeke image reported only a tentative ~1.5σ detection.
- The study was presented at AAS 247, accepted by The Astrophysical Journal, and coordinated follow-up is planned for a more favorable view around 2027.