The Probable Direct-Imaging Detection of the Stellar Companion to Betelgeuse

Fuente: arXiv
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Auteurs principaux: Howell, Steve B., Ciardi, David R., Clark, Catherine A., Hope, Douglas A., Littlefield, Colin, Furlan, Elise
Format: Preprint
Publié: 2025
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author Howell, Steve B.
Ciardi, David R.
Clark, Catherine A.
Hope, Douglas A.
Littlefield, Colin
Furlan, Elise
author_facet Howell, Steve B.
Ciardi, David R.
Clark, Catherine A.
Hope, Douglas A.
Littlefield, Colin
Furlan, Elise
contents Betelgeuse -- the closest M-supergiant to the Sun -- has recently been predicted to host a lower-mass stellar companion that orbits the primary with a period of $\sim 6$ years. The putative stellar companion is thought to cause the long photometric modulation observed in Betelgeuse, which cannot be explained by stellar pulsations. Additionally, radial velocity and astrometric data also point to a stellar companion. Here we present diffraction-limited optical speckle imaging observations obtained on the 8.1-meter Gemini North telescope in 2020 and 2024. The 2020 observations were taken during the Great Dimming event, and at a time when the stellar companion was predicted to be unobservable because it was directly in-line with Betelgeuse itself. The 2024 observations were taken three days after the predicted time of greatest elongation for the companion. A comparison of the 2020 and 2024 data reveal no companion in 2020 (as expected) and the probable detection of a companion in 2024. The presumed stellar companion has an angular separation and position angle of 52 mas and $115^\circ$ east of north, respectively, which is in excellent agreement with predictions from dynamical considerations. The detected companion is roughly six magnitudes fainter than Betelgeuse at 466 nm.\bf{While this is only a 1.5$σ$ detection, the results are in reasonable agreement with the predictions: the appearance of the companion at quadrature; the angular separation from Betelgeuse; the position angle with respect to Betelgeuse; the magnitude difference; and the estimated mass of the companion.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15749
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Probable Direct-Imaging Detection of the Stellar Companion to Betelgeuse
Howell, Steve B.
Ciardi, David R.
Clark, Catherine A.
Hope, Douglas A.
Littlefield, Colin
Furlan, Elise
Solar and Stellar Astrophysics
Betelgeuse -- the closest M-supergiant to the Sun -- has recently been predicted to host a lower-mass stellar companion that orbits the primary with a period of $\sim 6$ years. The putative stellar companion is thought to cause the long photometric modulation observed in Betelgeuse, which cannot be explained by stellar pulsations. Additionally, radial velocity and astrometric data also point to a stellar companion. Here we present diffraction-limited optical speckle imaging observations obtained on the 8.1-meter Gemini North telescope in 2020 and 2024. The 2020 observations were taken during the Great Dimming event, and at a time when the stellar companion was predicted to be unobservable because it was directly in-line with Betelgeuse itself. The 2024 observations were taken three days after the predicted time of greatest elongation for the companion. A comparison of the 2020 and 2024 data reveal no companion in 2020 (as expected) and the probable detection of a companion in 2024. The presumed stellar companion has an angular separation and position angle of 52 mas and $115^\circ$ east of north, respectively, which is in excellent agreement with predictions from dynamical considerations. The detected companion is roughly six magnitudes fainter than Betelgeuse at 466 nm.\bf{While this is only a 1.5$σ$ detection, the results are in reasonable agreement with the predictions: the appearance of the companion at quadrature; the angular separation from Betelgeuse; the position angle with respect to Betelgeuse; the magnitude difference; and the estimated mass of the companion.
title The Probable Direct-Imaging Detection of the Stellar Companion to Betelgeuse
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2507.15749