par Esseldeurs, Mats;Decin, Leen;De Ridder, Joris;Mori, Yoshiya;Karakas, Amanda I;Malfait, Jolien;Danilovich, Taïssa;Mathis, Stéphane;Richards, A.M.S.;Sahai, Raghvendra;Yates, Jeremy;Van De Sande, Marie;Baes, Maarten;Baudry, Alain;Bolte, Jan;Ceulemans, Thomas;De Ceuster, Frederik;El Mellah, Ileyk;Etoka, Sandra;Gottlieb, Carl C.A.;Herpin, Fabrice;Kervella, Pierre;Landri, Camille;Marinho, Louise;McDonald, Iain;Menten, Karl;Millar, Tom;Osborn, Zara;Pimpanuwat, Bannawit;Plane, John M C;Price, Daniel J.;Siess, Lionel 
;Vermeulen, Owen;Wong, Ka Tat
Référence Nature Astronomy, 10, 1, page (124-143)
Publication Publié, 2026-01-01
;Vermeulen, Owen;Wong, Ka TatRéférence Nature Astronomy, 10, 1, page (124-143)
Publication Publié, 2026-01-01
Article révisé par les pairs
| Résumé : | Close companions influence stellar evolution through tidal interactions, mass transfer and mass-loss effects. While such companions are detected around young stellar objects, main-sequence stars, red giants and compact objects, direct observational evidence of close-in companions around asymptotic giant branch (AGB) stars has remained elusive. Here we present (sub)millimetre time-domain imaging spectroscopy revealing the Keplerian motion of a close-in companion around the AGB star π1 Gruis. The companion, slightly more massive than the AGB star, is likely a main-sequence star. Unlike more evolved stars with companions at comparable distances, the companion of π1 Gruis follows a circular orbit, suggesting an eccentricity-generating mechanism during the late- or post-AGB phase. Our analysis suggests that model-predicted circularization rates may be underestimated. Our results highlight the potential of multi-epoch (sub)millimetre interferometry in detecting the Keplerian motion of close companions to giant stars and open avenues for our understanding of tidal interaction physics and binary evolution. |
