Betelgeuse is one of the most famous stars in the sky among both astronomers and the general public. Located in the left shoulder of Orion, the Hunter, both its brightness and red hue make it easy to spot. In 2025, direct evidence of a companion star to Betelgeuse was published by a team from the Gemini Observatory in Hawaii. While uncertainty in the observations left the evidence short of confirmation, the companion was assigned a name: Siwarha. The newest evidence, a longer study set for publication later this year, solidifies the claim of the companion’s existence.
It is not at all unusual for stars to trek through the Milky Way in pairs. While our Sun is a solitary star, a significant portion of the stars in our galaxy are in double- or triple-star systems, or even larger. Our nearest celestial neighbor, Proxima Centauri, has two companions. Some astronomers have suspected that Betelgeuse had a partner—unofficially nicknamed “Betelbuddy”—for decades, though some previous predictions turned out to be incorrect.
Independent of the 2025 findings, a research team at the Harvard and Smithsonian Center for Astrophysics utilized the Hubble Space Telescope along with two Earthbound observatories to track changes in Betelgeuse for nearly eight years. Their detailed observations build on the previous evidence, revealing a wake left behind by Siwarha’s orbit through the outer regions of the atmosphere of Betelgeuse. The lead author of the study, Andrea Dupree, compared the evidence to the wake left behind by a boat at sea. Even if you didn’t see the ship, it would be sufficient evidence for you to conclude a ship had just passed by. Their results were presented at a meeting of the American Astronomical Society on January 5, 2026, and are taken as more definitive confirmation.
Siwarha needs to be studied further to learn its characteristics. The research to date suggests it is probably comparable in mass to our Sun, with estimates ranging from about 0.5 to 2.0 solar masses. For comparison, Betelgeuse is around 15 to 20 times the mass of the Sun. At this size and young age—probably around 10 million years old—it’s possible Siwarha is a pre-main sequence star if it follows standard stellar evolutionary models. The main sequence is what astronomers call stars that are in their longest, most stable phase of life, with nuclear fusion of hydrogen taking place in their cores. Pre-main sequence stars are almost fully formed but haven’t yet grown hot enough to ignite fusion. However, since Siwarha essentially lives inside the outer atmosphere of Betelgeuse, its evolution may not match standard models. Regardless of its current state of development, Siwarha won’t enjoy the billions of years of life our Sun has. A little more about Betelgeuse will explain.
Betelgeuse itself stirs wonder for several reasons. One is its enormous size. Betelgeuse is a red supergiant star, hundreds of times the diameter of our Sun. If you could replace our Sun with Betelgeuse right now, you would be inside the star. It is so large that its surface would extend out to roughly the orbit of Jupiter. Partly due to that immensity, it is also one of the few stars that astronomers can image and see detail on its surface. Most stars, even supergiants, are so far away that they appear as simple points of light even through the most powerful telescopes. Being somewhere in the range of 500 to 700 light-years distant (its distance is a subject of debate), Betelgeuse is close enough for its size to allow some limited direct study of its surface and atmosphere. This is what allowed the Harvard-Smithsonian team to confirm the presence of Siwarha.
Another reason Betelgeuse fascinates is that astronomers believe it is nearing the end of its relatively short lifespan. When that end is reached, it is very likely that the star will go supernova. This may happen in the next 100,000 years. There’s no way to know for certain when, though modeling suggests the chances of it happening within our lifetimes are slim to none. But if we get lucky, enjoy the show. To the best of our knowledge, there hasn’t been a supernova in our galaxy visible to the naked eye since the early 1600s. When Betelgeuse goes, it will light up the night sky like a second moon and be visible even in daytime.
This makes the newly-discovered companion more important. Astronomers keep a close eye on Betelgeuse because of its impending doom. This is the first time modern astronomers will have the opportunity and ability to study a nearby star as it approaches supernova. There are still open questions about the exact physical mechanism that causes a supernova. Keeping a close eye on Betelgeuse could help us learn more about this process, and maybe even discover telltale signs that the collapse is about to occur. This is also why Siwarha will be a short-lived star: when Betelgeuse goes supernova, Siwarha will be destroyed. Before that, it may be engulfed by its larger partner as Betelgeuse swells up with age. Siwarha’s prospects are not good.
Still, it is a very meaningful discovery. For years, there were some unexplained phenomena observed in Betelgeuse’s brightness. Several theories were proposed to explain these anomalies, one being that Betelgeuse had a companion. Now it appears that theory was correct. That potentially explains one of the variations observed over the years. Now astronomers can refine their theories and take the existence of this companion into account for future observations. This will help them better understand exactly what is going on with Betelgeuse as it nears its spectacular end.
In 2027, astronomers will get a chance to study Siwarha in more detail. It is currently behind Betelgeuse from our perspective, but calculations of its orbit suggest it will be visible again starting next year.
Tidings from the Void 