Astronomers capture clearest image of Betelgeuse's hidden companion
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Astronomers led by Miguel Montargès used ESO's Very Large Telescope to capture the clearest image yet of Betelgeuse B, a companion star orbiting the red supergiant Betelgeuse. The observations, made in December 2024, suggest the companion is two to three times the mass of the Sun, more massive than earlier estimates. The finding concludes a century-long search for a stellar companion to Betelgeuse.
Key Facts
- The study was published today in Astronomy & Astrophysics.
- The companion, Betelgeuse B, is estimated to have two to three times the mass of the Sun.
- Observations were made in December 2024 with the SPHERE instrument on ESO's Very Large Telescope in Chile's Atacama Desert.
- Two studies published in 2024 predicted that Betelgeuse B would reach its greatest apparent separation from Betelgeuse in December 2024.
The Discovery
A team led by French astronomer Miguel Montargès used the European Southern Observatory's Very Large Telescope to capture the clearest image so far of Betelgeuse B. Montargès, an astronomer at the Observatoire de Paris – PSL, is the lead author of the study published today in Astronomy & Astrophysics. "This is the conclusion of a century-long quest," Montargès said. The researchers directly imaged Betelgeuse B, detecting light coming from the companion itself.
Observational Evidence
The observations were made in December 2024, when Betelgeuse B reached its greatest apparent separation from Betelgeuse. The team used the SPHERE instrument on ESO's VLT in Chile's Atacama Desert. Previous observations had provided clues to the companion's existence, including a possible direct detection with the Gemini North Telescope in Hawaiʻi. The new VLT observations provide the strongest evidence so far and the clearest image yet of Betelgeuse B.
Mass Estimates
Scientists had initially estimated that the companion would have roughly the same mass as the Sun. The new observations instead suggest that Betelgeuse B is considerably larger, with about two to three times the Sun's mass. "Because it is more massive than predicted, we see it!" Montargès explained. Montargès added that discovering a nearby companion more massive and brighter than the Sun around such a well-studied star is remarkable.
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Astronomers capture clearest image of Betelgeuse's hidden companion
