Hidden Companions to Intermediate-mass Stars. Upgraded Multiplicity 5 → 6. XXVII. Discovery of a 1.45M ⊙, 0.6 au Companion to Beta2 Tucanae C*
Year: 2025
Type: article
Abstract: Beta2 Tucanae (β 2 Tuc) is a nearby a = 22 au visual binary (C+D) and one of the brighter members of the young Tucana–Horologium association. Here we report on a VLTI/GRAVITY interferometric observation which revealed that β 2 Tuc is actually a rather compact triple system: the primary is itself a close binary (Ca+Cb) with a projected separation ρ = 13.56 mas ↔ 0.59 au and a K band flux ratio of 56.65%. We estimate isochrone masses M Ca ≃ 2.0M ⊙, M Cb ≃ 1.45M ⊙ and M D ≃ 1.45M ⊙. Together with its wide (∼1200 au) companion β 1 Tuc (itself a binary) and very wide (∼23,000 au) companion β 3 Tuc, this makes the β Tuc system a sextuple. The compactness and rather low effective hierarchy of β 2 Tuc a out ( 1 − e out ) a in ≲ 7 make it a particularly interesting system for triple dynamics and stability studies.
Source: Research Notes of the AAS
Authors: Idel Waisberg, Ygal Klein, Boaz Katz
Institution: Weizmann Institute of Science
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4410155551