Referred to as Alpha Ori B, or the "Betelbuddy," by astrophysicist Jared Goldberg, this companion star might influence Betelgeuse's brightness by clearing away light-blocking dust during its orbit. Goldberg and his research team presented their findings in *The Astrophysical Journal*.

"We ruled out every intrinsic source of variability that we could think of," Goldberg explained, noting that the data strongly pointed to the presence of a companion. "The only hypothesis that seemed to fit is that Betelgeuse has a companion."

Goldberg collaborated with Meridith Joyce from the University of Wyoming and Laszlo Molnar from the Konkoly Observatory in Hungary.

Betelgeuse, a massive red giant, is nearing the end of its life and will eventually explode in a supernova visible from Earth. As a variable star, it experiences fluctuations in brightness, or "heartbeats," over time-one of about a year and another lasting around six years.

The study explored whether external factors, like an orbiting companion, might explain the star's longer pulsation. This "long secondary period" is thought to occur when a companion disrupts surrounding dust, affecting how much light from the star reaches Earth.

The team examined alternative explanations such as magnetic field shifts or internal processes within Betelgeuse. However, after thorough analysis, the Betelbuddy theory was deemed most plausible. Goldberg remarked, "Nothing else added up. Basically, if there's no Betelbuddy, then that means there's something way weirder going on."

The exact nature of the Betelbuddy remains unclear, though the researchers speculate it could be a star up to twice the mass of the Sun. Joyce added, "A sunlike star is the most probable type of companion," while also considering a more exotic possibility-a neutron star. However, no X-ray evidence supporting the latter theory has been found.

The team plans to gather direct observational evidence of the Betelbuddy, with a possible window of visibility in early December.

"We need to confirm that Betelbuddy actually exists," said Molnar, adding that the team is preparing proposals for further observations.

The collaborative nature of the research was critical to the study's success, Joyce emphasized, highlighting the diverse expertise within the team. Molnar concluded by expressing his excitement at the potential discovery of a hidden companion star within such a well-studied system.

Research Report:A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in a Orionis

Related Links
Flatiron Institute's Center for Computational Astrophysics
Stellar Chemistry, The Universe And All Within It