After decades of searching: Betelgeuse's elusive companion star discovered

Using the Gemini Telescope in Hawaii, astronomers have managed to locate a young star orbiting Betelgeuse, within its atmosphere – a discovery that explains the red supergiant's brightness fluctuations.

Proofreading:
1)
3) "And this allows for the high resolution of Alupka.." -> "The discovery is made possible thanks to the high resolution of Alupka."
4) "Strong tidal forces" -> "Strong gravitational forces"
5) "Will occur in the next 10,000 (years?)"

Gemini North Telescope Hawaii discovers hidden companion to Betelgeuse, shedding light on ancient stellar mystery

Using the 'Alopeke' instrument on the Gemini North telescope, astronomers have identified a companion star in very close orbit around Betelgeuse. This breakthrough answers the long-standing question about Betelgeuse's variable brightness and sheds light on processes at work in other red giants that show similar variability.

Betelgeuse is among the brightest stars visible from Earth and the closest known red supergiant. It is massive, with a radius about 700 times that of the Sun. Although only about 10 million years old – young by astronomical standards – it is already in the final stages of its stellar life.

Located in the shoulder of the Orion constellation, Betelgeuse has been visible without instruments for thousands of years, and observers have long noted its fluctuating brightness. Scientists have determined that the star exhibits a primary brightness variation every 400 days, along with a longer secondary cycle lasting about six years.

The Great Dimness and Renewed Interest

In 2019 and 2020, Betelgeuse underwent a dramatic decrease in brightness, an event known as the “Great Dimming.” This sudden change led to speculation that the star might soon explode as a supernova. But researchers ultimately found that the cause was a massive dust cloud ejected from the star.

Although the source of the dimming was identified, the unusual event renewed scientific interest in Betelgeuse, and previously collected data were reexamined. One of these analyses suggested that the star's six-year brightness cycle might be caused by the influence of a nearby companion star. But previous attempts to find this companion using the Hubble and Chandra telescopes were unsuccessful.

Now, a research team led by Steve Howell has discovered the elusive companion for the first time. The team used a spot imager called Alupaka (Hawaiian for "fox"), which is mounted on the Gemini North telescope. Spot imaging works by taking very short exposures to minimize distortions caused by Earth's atmosphere. This method achieves very high resolution, and together with Gemini North's 8.1-meter mirror, the team was able to discover the faint companion star near Betelgeuse.

A weak young star inside Betelgeuse's atmosphere

Analysis of the companion star's light allowed Howell and his team to determine the star's characteristics. They found that it is six orders of magnitude fainter than Betelgeuse in visible light, has an estimated mass of about 1.5 times that of the Sun, and appears to be a type A or B pre-main sequence star—a young, hot blue-white star that has not yet begun to burn hydrogen in its core.

The companion is relatively close to Betelgeuse – about four times the distance between Earth and the Sun. This discovery is the first time a close companion has been discovered orbiting a supergiant star. Even more impressively, the companion orbits within Betelgeuse’s extended outer atmosphere, a discovery made possible by the high resolution of Alupka.

"Gemini North's ability to achieve high angular resolutions and sharp contrast enabled the direct detection of Betelgeuse's companion," says Howell. He also explains that Alupka did what no telescope had done before: "In the papers that predicted Betelgeuse's companion, it was believed that probably no one would ever be able to image it."

Insights into the future of Betelgeuses and stellar behavior

This discovery provides a clear picture of the future life and death of this red supergiant. Betelgeuse and its companion likely formed at the same time. But the companion's lifespan will be short because strong tidal forces will cause it to spiral into Betelgeuse toward its end, which scientists estimate will occur in the next 10,000 years. The discovery also helps explain why similar red supergiants can undergo periodic brightness changes on timescales of many years, and Hewl hopes more research will follow.

for the scientific article

More of the topic in Hayadan:

• New evidence that the nearby red giant Betelgeuse has a hidden companion
• 2012 - New craze: Betelgeuse will explode and this will apparently hurt the Earth
• Beetlejuice: The star continues to behave mysteriously - here's what will happen if it explodes
• Rare photo: The massive star Betelgeuse is on its way to collide with a wall of cosmic dust