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\n Astronomers have observed what they believe to be a never-before-seen companion star orbiting Betelgeuse<\/a>, a pulsating red supergiant star in the shoulder of the Orion constellation.\n <\/p>\n \n One of the best known and most luminous stars in the night sky, Betelgeuse has long intrigued anyone who has gazed up and seen its reddish tint, which is visible to the naked eye. What has most fascinated astronomers, however, is that its brightness has been known to change over time. Now, they think the newly detected celestial object may hold the key to understanding Betelgeuse\u2019s varying brightness.\n <\/p>\n \n From late 2019 to the beginning of 2020, Betelgeuse dimmed so sharply that astronomers thought the star was on the brink of exploding in a supernova. Since the event, called the \u201cGreat Dimming<\/a>,\u201d teams of astronomers have determined that the star ejected a large dust cloud, which temporarily blocked some of its light from Earth\u2019s perspective.\n <\/p>\n \n The Great Dimming led to an increased interest in solving longstanding mysteries about one of the cosmos\u2019 most observed stars \u2014 such as why its brightness appears to fluctuate regularly over a six-year cycle and has for decades.\n <\/p>\n \n A team of astronomers has now discovered an explanation. Using an instrument on the Gemini North telescope in Hawaii, they employed an unusual imaging technique to get a glimpse of a suspected companion star, colloquially called \u201cBetelbuddy,\u201d that builds on a previous theory.\n <\/p>\n \n They suggest calling the star Siwarha, or \u201cher bracelet,\u201d an Arabic name befitting the companion to Betelgeuse, which means \u201cHand of the Giant.\u201d (\u201cElgeuse\u201d is also the historic Arabic name of the Orion constellation.)\n <\/p>\n \n Understanding more about the dynamic between Betelgeuse and its companion star, also referred to as Ori B in a new study published Thursday in The Astrophysical Journal Letters<\/a>, could shed light on the entwined fate of both stars.\n <\/p>\n \n As a supergiant star, Betelgeuse is immense. Compared with our sun, it\u2019s about 700 times the radius and contains 18 times as much mass, said lead study author Steve Howell, a senior research scientist at NASA Ames Research Center in California. If our sun were replaced with Betelgeuse, the star would not only engulf Earth and all the inner planets but reach past the orbit of Jupiter, according to NASA<\/a>. It also shines 7,500 to 14,000 times as bright as the sun.\n <\/p>\n \n At 10 million years old, Betelgeuse is a fraction of the age of our sun, which is estimated to be 4.5 billion years old. However, Betelgeuse\u2019s enormousness means it has already burned through all the hydrogen at its core, causing it to expand as it nears the end of its life.\n <\/p>\n \n Years of observations have shown that its luminosity varies periodically about every 416 days, growing fainter and then brighter. This pulsation is typical of red supergiant stars.\n <\/p>\n \n But Betelgeuse displays an unusual pattern on top of that. \u201cIt has been noted for decades that Betelgeuse also shows a much longer period (of variation) of about 2,170 days (about six years) which remained unexplained,\u201d Howell wrote in an email.\n <\/p>\n \n Two independent groups of astronomers published papers in 2024 suggesting that an unseen companion star could cause the variability. The Hubble Space Telescope and NASA\u2019s Chandra X-Ray Observatory, however, could see no evidence of such a star. Betelgeuse\u2019s size and brightness have posed challenges to attempts to spot a companion.\n <\/p>\n \n To see both Betelgeuse and its companion, an image has to be both high-resolution and high-contrast, said Jared Goldberg, a research fellow at the Flatiron Institute\u2019s Center for Computational Astrophysics. Goldberg authored a November study<\/a> suggesting Betelgeuse may have a companion star, but he was not involved with the new research.\n <\/p>\n \n \u201cNormally, the Earth\u2019s atmosphere makes it hard to do this for the same reason that stars twinkle \u2014 the moving gas in the atmosphere scatters the starlight around,\u201d Goldberg said.\n <\/p>\n \n Howell\u2019s team decided to use a speckle imager called \u2018Alopeke, which means \u201cfox\u201d in Hawaiian, to search for the companion.\n <\/p>\n \n \u201cSpeckle imaging is a technique that obtained many thousands of very short exposures of an astronomical object,\u201d Howell said. \u201cThese images are so short that they do not look like stars or galaxies at all, but a blob of \u2018speckles.\u2019\u201d\n <\/p>\n \n The speckles are due to distortions from Earth\u2019s atmosphere. The thousands of brief images are processed in a way that removes the atmospheric blurring, resulting in a high-resolution telescope image, Howell said.\n <\/p>\n
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<\/p>\n![\"Gemini](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/07\/iotw2443a.jpg\")
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