# Hidden Companion Star Siwarha Distorts Betelgeuse's Atmosphere New radio observations suggest a companion star physically disturbs the red supergiant's outer layers. - **Source:** [Latest Science News -- ScienceDaily](https://brifing.si/source/0eef8637-6c5b-4e79-8f5b-6c9c6b36cf16) - **Published:** 2026-11-04 - **Topic:** [Business](https://brifing.si/c/business) - **Original article:** - **On Brifing:** https://brifing.si/s/c9f6452c-155d-485b-ae6f-015188088f45 ## Atmospheric Anomalies Detected Astronomers identified unusual shape changes within the massive atmosphere of Betelgeuse, a prominent red supergiant. By analyzing radio data from the NSF VLA and ALMA, researchers observed that the star's outer layers do not remain perfectly spherical. These distortions suggest an unseen physical interaction occurring within the star's extended gaseous environment. ## The Role of Siwarha Evidence points to Siwarha, a companion star orbiting extremely close to Betelgeuse, as the primary cause of these disturbances. First proposed in 2024 to explain a 2,100-day brightness cycle, Siwarha follows an orbit roughly twice the radius of the giant star. It physically moves through the gas, creating detectable atmospheric wakes. ## Radio Frequency Analysis Led by Dr. Lynn D. Matthews, the research team utilized seven radio frequencies between 22 GHz and 485 GHz to map Betelgeuse. This multi-frequency approach allowed scientists to resolve different depths of the star's atmosphere, from the photosphere outward, providing a structural reconstruction that was previously impossible with standard optical observations alone. ## Confirming the MOLsphere The study confirmed the existence of the MOLsphere, a cool molecular gas layer located between the photosphere and the chromosphere. ALMA observations revealed temperatures dropping to 2,200 Kelvin in this region, significantly cooler than the visible surface. This direct measurement validates long-standing theories regarding the temperature minimum within the supergiant's complex outer atmosphere. ## Great Dimming Context These findings provide critical context for the 2019-2020 Great Dimming event, where Betelgeuse lost significant brightness. Previous data showed low temperatures and shock waves preceding the ejection of a billion tons of material. The current atmospheric warming suggests the star has largely recovered, though the companion's influence remains a persistent factor. ## Ellipticity and Orbital Mechanics Researchers measured the atmosphere's ellipticity, finding it becomes more elongated when Siwarha reaches its greatest apparent separation. Conversely, the star appears rounder when the companion passes in front of or behind the giant. This correlation provides strong evidence that gravity and physical passage are actively reshaping the star's outer gaseous layers. ## Limitations and Future Research While the connection between Siwarha and the atmospheric distortions is compelling, scientists emphasize that more data is required. Future observations covering the full orbital cycle are necessary to quantify the impact. The upcoming Next Generation Very Large Array is expected to offer the resolution needed to definitively map these complex stellar interactions. ## Evolutionary Implications Understanding how companion stars influence red supergiants is vital for mapping the final stages of stellar evolution. These interactions likely dictate how aging stars lose mass before their eventual demise. By studying these dynamics, astronomers gain deeper insights into the complicated processes that shape the life cycles of the universe's most massive stars. ## Sources covering this story - https://www.sciencedaily.com/releases/2026/11/261103003149.htm — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._