Key Takeaways:
– Two independent studies suggest Betelgeuse, the red supergiant, has a tiny companion star.
– The unseen star is believed to have approximately the same mass as the Sun.
– The Sun-like star completes an orbit around Betelgeuse approximately every 2,100 days.
– Gravitational pull from this companion star may explain Betelgeuse’s behavioral anomalies like cycles of brightening and dimming.
– Despite the compelling evidence, proving the existence of this companion star may prove challenging, if not impossible.
Astronomical Companion Camouflaged in Plain Sight
Betelgeuse, famous in astronomical circles as the red supergiant that marks Orion’s left shoulder, appears not to be a lone star in the cosmos. Soundings from two independent studies point towards the presence of an unseen star, roughly with the same mass as our Sun, which orbits Betelgeuse approximately every 2,100 days.
Astrophysicist Morgan MacLeod and a team from the Harvard & Smithsonian Center for Astrophysics made the surprising discovery by linking a six-year cycle of Betelgeuse going from brightening to dimming, and vice versa, to the suspected companion star affecting the orbit.
Spin on a Century Old Theory
This fresh discovery breathes new life into a theory that was proposed well over a century ago. Noted English astronomer Henry Cozier Plummer proposed in 1908 that a cyclic variance in the light of Betelgeuse could be due to a companion star’s gravitational force.
In the intervening years, the idea of a companion star gradually drifted into obscurity as Betelgeuse presented a growing list of complex behaviors. Bursts of material being sent into space and a rhythm of ‘pulsation’ marked by the star expanding and contracting on a 400-day cycle, to name a few.
Resurgence of an Old Mystery
After the notable ‘Great Dimming’ phase of Betelgeuse in 2019, interest in its singular behavior patterns was reignited among astronomers. With a reliable 128 years of observations at their disposal, the Harvard & Smithsonian Center for Astrophysics team postulated that the six-year cycle might indeed be the consequence of gravitational effects from a companion star.
Calculations, based on this result along with other measurements, proposed the companion star’s mass to be around 0.6 times that of the Sun, orbiting every 2,110 days at slightly more than twice the distance of Betelgeuse’s radius.
Supporting these measurements, a team led by Jared Goldberg from the Flatiron Institute in New York, using the last 20 years of Betelgeuse’s movement measurements, has suggested the presence of a star with a mass 1.2 times the Sun’s, completing its orbit every 2,170 days.
In Search of a Star Companion
With the resurgence of the companion star theory, the academic community is abuzz with the thrilling possibility. Miguel Montargès from the Paris Observatory said, “These are very exciting works: we all want to find Betelgeuse’s companion,” further adding that if proven, this could have significant implications for our understanding of red supergiants.
However, even if the existence of this companion is validated, it seems fated for a catastrophic ending. The companion star’s orbit is gradually reducing as Betelgeuse appears to be siphoning off its angular momentum. Experts estimate that in about 10,000 years, Betelgeuse will consume its smaller companion entirely. Until then, the astronomical community will continue to probe the mysteries of these celestial bodies for the further enrichment of our understanding of the cosmos.