Astronomers have unveiled a significant discovery regarding the red supergiant star Betelgeuse, confirming the existence of a hidden companion star, named Siwarha. This revelation stems from nearly eight years of observations using the Hubble Space Telescope and ground-based observatories located in Arizona and the Canary Islands.
Betelgeuse has long been known for its fluctuating brightness, which is primarily due to internal processes common among aging stars. The star exhibits a regular pulsing cycle of approximately 400 days. However, researchers were perplexed by a second, longer cycle of around 2,100 days that did not align with existing theories on stellar behavior. This secondary cycle occurred consistently, yet scientists could not explain its origin.
Leading theories suggested that a dim companion star might be influencing Betelgeuse from a distance, but definitive evidence had remained elusive until now.
Discovery of the Companion Star
The breakthrough came when astronomers detected a dense trail of gas in Betelgeuse’s atmosphere, attributed to the movement of Siwarha. This “wake” is comparable to a ship cutting through water, disrupting the star’s outer layers. As Siwarha orbits Betelgeuse, it subtly modifies the star’s ultraviolet emissions, particularly from ionized iron.
According to NASA, when Siwarha passes in front of Betelgeuse, there is a noticeable spike in brightness. As it continues its orbit, the gas trail behind it absorbs some of this radiation, leading to a reduction in brightness. This pattern perfectly matches the previously mysterious 2,109-day cycle.
In an official statement, the study’s lead author, Andrea K. Dupree, remarked on the significance of this finding. “The companion star creates a ripple effect in Betelgeuse’s atmosphere that we can actually see in the data,” she stated. “For the first time, we’re seeing direct signs of this wake, confirming that Betelgeuse really does have a hidden companion shaping its appearance and behavior.”
Looking Ahead
Currently, Siwarha has moved behind Betelgeuse and is not expected to reappear until August 2027. In the meantime, astronomers will continue monitoring the star, utilizing the knowledge gained from this discovery to better understand the interactions between Betelgeuse and its hidden companion.
This finding not only enhances our knowledge of Betelgeuse but also opens new avenues for studying the dynamics of binary star systems. The intricate dance between stars like Betelgeuse and their companions offers invaluable insights into the life cycles of stars and the complex behaviors that govern them.
