{"id":13276,"date":"2025-07-22T11:37:10","date_gmt":"2025-07-22T11:37:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/13276\/"},"modified":"2025-07-22T11:37:10","modified_gmt":"2025-07-22T11:37:10","slug":"gemini-north-discovers-long-predicted-stellar-companion-of-betelgeuse","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/13276\/","title":{"rendered":"Gemini North discovers long-predicted stellar companion of Betelgeuse"},"content":{"rendered":"

<\/p>\n

\"Betelgeuse<\/p>\n

<\/a><\/p>\n

image:\u00a0<\/p>\n

Using the NASA-NSF-funded\u00a0\u2018Alopeke<\/a>\u00a0instrument on the\u00a0Gemini North telescope<\/a>, one half of the\u00a0International Gemini Observatory<\/a>, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab, astronomers have discovered a companion star in an incredibly tight orbit around\u00a0Betelgeuse<\/a>. This discovery answers the millennia-old question of why this famous star experiences a roughly six-year-long periodic change in its brightness, and provides insight into the physical mechanisms behind other variable red supergiants. The companion star appears blue here because, based on the team\u2019s analysis, it is likely an\u00a0A- or B-type<\/a>\u00a0star, both of which are blue-white due to their high temperatures.<\/p>\n

\u2018Alopeke is funded by the NASA-NSF Exoplanet Observational Research Program (NN-EXPLORE).<\/p>\n

view more\u00a0<\/a><\/p>\n

Credit: International Gemini Observatory\/NOIRLab\/NSF\/AURA
\nImage Processing: M. Zamani (NSF NOIRLab)<\/p>\n

Betelgeuse<\/a>\u00a0is one of the brightest stars in the night sky, and the closest\u00a0red supergiant<\/a>\u00a0to Earth. It has an enormous volume, spanning a radius around 700 times that of the Sun. Despite only being ten million years old, which is considered young by astronomy standards, it\u2019s late in its life. Located in the\u00a0shoulder of the constellation Orion<\/a>, people have observed Betelgeuse with the naked eye\u00a0for millennia<\/a>, noticing that the star changes in brightness over time. Astronomers established that Betelgeuse has a main period of variability of around 400 days and a more extended secondary period of around six years.<\/p>\n

In 2019 and 2020, there was a steep decrease in Betelgeuse\u2019s brightness \u2014 an event referred to as the \u2018Great Dimming.\u2019 The event led some to believe that a supernova death was quickly approaching, but scientists were able to determine the dimming was actually caused by a\u00a0large cloud of dust<\/a>\u00a0ejected from Betelgeuse.<\/p>\n

The Great Dimming mystery was solved, but the event sparked a renewed interest in studying Betelgeuse, which brought about new analyses of archival data on the star. One analysis led scientists to propose that the cause of Betelgeuse\u2019s six-year variability is the presence of a companion star\u00a0[1]<\/a>. But when the\u00a0Hubble Space Telescope<\/a>\u00a0and the\u00a0Chandra X-Ray Observatory<\/a>\u00a0searched for this companion, no detections were made.<\/p>\n

The companion star has now been detected for the first time by a team of astrophysicists led by Steve Howell, a senior research scientist at\u00a0NASA Ames Research Center<\/a>. They observed Betelgeuse using a speckle imager called\u00a0\u2018Alopeke<\/a>. \u2018Alopeke, which means \u2018fox\u2019 in Hawaiian, is funded by the NASA\u2013NSF Exoplanet Observational Research Program (NN-EXPLORE) and is mounted on the\u00a0Gemini North telescope<\/a>, one half of the\u00a0International Gemini Observatory<\/a>, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab.<\/p>\n

Speckle imaging<\/a>\u00a0is an astronomical imaging technique that uses very short exposure times to freeze out the distortions in images caused by Earth\u2019s atmosphere. This technique enables high resolution, which, when combined with the light collecting power of Gemini North\u2019s 8.1-meter mirror, allowed for Betelgeuse\u2019s faint companion to be directly detected.<\/p>\n

Analysis of the companion star\u2019s light allowed Howell and his team to determine the companion star\u2019s characteristics. They found that it is six magnitudes fainter than Betelgeuse in the optical wavelength range, it has an estimated mass of around 1.5 times that of the Sun, and it appears to be an\u00a0A- or B-type<\/a>\u00a0pre-main-sequence star<\/a>\u00a0\u2014 a hot, young, blue-white star that has not yet initiated hydrogen burning in its core.<\/p>\n

The companion is at a relatively close distance away from the surface of Betelgeuse \u2014 about four times the distance between the Earth and the Sun. This discovery is the first time a close-in stellar companion has been detected orbiting a supergiant star. Even more impressive \u2014 the companion orbits well within Betelgeuse\u2019s outer extended atmosphere, proving the incredible resolving abilities of \u2018Alopeke.<\/p>\n

\u201cGemini North\u2019s ability to obtain high angular resolutions and sharp contrasts allowed the companion of Betelgeuse to be directly detected,\u201d\u00a0says Howell. Furthermore, he explains that \u2018Alopeke did what no other telescope has done before:\u00a0\u201cPapers that predicted Betelgeuse\u2019s companion believed that no one would likely ever be able to image it.\u201d<\/p>\n

This discovery provides a clearer picture of this red supergiant\u2019s life and future death. Betelgeuse and its companion star were likely born at the same time. However, the companion star will have a shortened lifespan as strong tidal forces will cause it to spiral into Betelgeuse and meet its demise, which scientists estimate will occur within the next 10,000 years.<\/p>\n

The discovery also helps to explain why similar red supergiant stars might undergo periodic changes in their brightness on the scale of many years. Howell shares his hope for further studies in this area:\u00a0\u201cThis detection was at the very extremes of what can be accomplished with Gemini in terms of high-angular resolution imaging, and it worked. This now opens the door for other observational pursuits of a similar nature.\u201d<\/p>\n

Martin Still, NSF program director for the International Gemini Observatory adds:\u00a0\u201cThe speckle capabilities provided by the International Gemini Observatory continue to be a spectacular tool, open to all astronomers for a wide range of astronomy applications. Delivering the solution to the Betelgeuse problem that has stood for hundreds of years will stand as an evocative highlight achievement.\u201d<\/p>\n

Another opportunity to study Betelgeuse\u2019s stellar companion will occur in November 2027 when it returns to its furthest separation from Betelgeuse, and thus easiest to detect. Howell and his team look forward to observations of Betelgeuse before and during this event to better constrain the nature of the companion.<\/p>\n

Notes<\/p>\n

[1] Two papers released in 2024 used decades of observations of Betelgeuse from many observers around the world to predict the orbit and location of the companion star (see DOI:\u00a010.3847\/1538-4357\/ad93c8<\/a>\u00a0and DOI:\u00a010.3847\/1538-4357\/ad87f4<\/a>).<\/p>\n

More information<\/p>\n

This research was presented in a paper titled \u201cProbable Direct Imaging Discovery of the Stellar Companion to Betelgeuse\u201d to appear in\u00a0The Astrophysical Journal Letters. DOI: 10.3847\/2041-8213\/adeaaf<\/p>\n

The team is composed of Steve B. Howell (NASA Ames Research Center), David R. Ciardi (NASA Exoplanet Science Institute-Caltech\/IPAC), Catherine A. Clark (NASA Exoplanet Science Institute-Caltech\/IPAC), Douglas A. Hope (Georgia Tech Research Institute, Georgia State University), Colin Littlefield (NASA Ames Research Center, Bay Area Environmental Research Institute), Elise Furlan (NASA Exoplanet Science Institute-Caltech\/IPAC).<\/p>\n

NSF NOIRLab<\/a>, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the\u00a0International Gemini Observatory<\/a>\u00a0(a facility of\u00a0NSF<\/a>,\u00a0NRC\u2013Canada<\/a>,\u00a0ANID\u2013Chile<\/a>,\u00a0MCTIC\u2013Brazil<\/a>,\u00a0MINCyT\u2013Argentina<\/a>, and\u00a0KASI\u2013Republic of Korea<\/a>), NSF Kitt Peak National Observatory (KPNO<\/a>), NSF Cerro Tololo Inter-American Observatory (CTIO<\/a>), the Community Science and Data Center (CSDC<\/a>), and NSF\u2013DOE\u00a0Vera C. Rubin Observatory<\/a>\u00a0(in cooperation with\u00a0DOE<\/a>\u2019s\u00a0SLAC<\/a>\u00a0National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA<\/a>) under a cooperative agreement with\u00a0NSF<\/a>\u00a0and is headquartered in Tucson, Arizona.\u00a0<\/p>\n

The scientific community is honored to have the opportunity to conduct astronomical research on\u00a0I\u2019oligam Du\u2019ag\u00a0(Kitt Peak) in Arizona, on\u00a0Maunakea\u00a0in Hawai\u2018i, and on Cerro Tololo and Cerro Pach\u00f3n in Chile. We recognize and acknowledge the very significant cultural role and reverence of\u00a0I\u2019oligam Du\u2019ag\u00a0to the Tohono O\u2019odham Nation, and\u00a0Maunakea\u00a0to the\u00a0Kanaka Maoli\u00a0(Native Hawaiians) community.<\/p>\n

The NASA\u2013NSF Exoplanet Observational Research Program (NN-EXPLORE) is a joint initiative to advance U.S. exoplanet science by providing the community with access to cutting-edge, ground-based observational facilities. Managed by NASA\u2019s Exoplanet Exploration Program (ExEP), NN-EXPLORE supports and enhances the scientific return of space missions such as Kepler, TESS, HST, and JWST by enabling essential follow-up observations from the ground\u2014creating strong synergies between space-based discoveries and ground-based characterization. ExEP is located at the Jet Propulsion Laboratory. More information at\u00a0https:\/\/exoplanets.nasa.gov\/exep\/NNExplore\/overview\/<\/a>.<\/p>\n

Links<\/p>\n

Journal<\/p>\n

The Astrophysical Journal Letters<\/p>\n

Article Title<\/p>\n

Probable Direct Imaging Discovery of the Stellar Companion to Betelgeuse<\/p>\n

Article Publication Date<\/p>\n

24-Jul-2025<\/p>\n

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.<\/p>\n","protected":false},"excerpt":{"rendered":"image:\u00a0 Using the NASA-NSF-funded\u00a0\u2018Alopeke\u00a0instrument on the\u00a0Gemini North telescope, one half of the\u00a0International Gemini Observatory, partly funded by the…\n","protected":false},"author":2,"featured_media":13277,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[64,63,128,285],"class_list":["post-13276","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-au","tag-australia","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/13276","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=13276"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/13276\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/13277"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=13276"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=13276"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=13276"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}