Gemini North telescope discovers long-predicted stellar companion of Betelgeuse

layer8 | 124 points

The companion star "has an estimated mass of about 1.5 times that of the Sun and appears to be an A- or B-type main pre-sequence star, i.e. a hot, young, bluish-white star that has not yet begun to burn hydrogen in its core... The companion is located at a relatively close distance to Betelgeuse, about 4 times the distance between Earth and the Sun. This discovery is the first time a stellar companion has been detected orbiting so close to a red supergiant star. Even more surprising is that the companion orbits inside Betelgeuse's outer atmosphere."

chasil | 13 hours ago

The paper is here: https://arxiv.org/abs/2507.15749

The detection appears to be statistically very marginal, 1.5sigma, and the image contains a very similar bright spot on the opposite side of the star (which, for some reason, does not warrant a detection claim).

e23c16 | 11 hours ago

Wow, so it's currently shining purely from gravitational energy release, not nuclear reactions. I hadn't realized that it was possible or that we'd be able to see something of the sort.

mkw5053 | 10 hours ago

At least they got to see it before Betelgeuse went supernovae. Do we have examples of the results of the companion star when the main star lets go?

dylan604 | 13 hours ago

The sequel wasn't as good.

_spduchamp | 4 hours ago

Could this explain why Betelgeuse's brightness seems to vary so much?

edit: apparently, yep, that's why.

pavel_lishin | 13 hours ago

Any comments from Ford Prefect about this?

SirLJ | 3 hours ago

dumb question: If a pre-sequence star is assimilated into a larger EOL star, does all the newly assimilated fuel delay or accellerate the larger star's demise?

anjel | 11 hours ago

The submitted URL was https://noirlab.edu/public/news/noirlab2523/, but for some reason is frequently returning the Spanish version of the article. We replaced it with a link to a third-party article and will include the noirlab.edu link at the top.

dang | 12 hours ago

Gemini North is a telescope, not some new feature of Google's AI model https://en.wikipedia.org/wiki/Gemini_Observatory

>Gemini North telescope in Hawai‘i reveals never-before-seen companion to Betelgeuse, solving millennia-old mystery

htrp | 13 hours ago

Is it Beetlejuice, Beetlejuice?

AverageSavage | 8 hours ago