Hidden Companions to Intermediate-mass Stars. XV. Discovery of a 1.2M ⊙, 8.4 au Companion to the δ Scuti star HIP 41375 = 2 Hydrae*

Abstract

Abstract 2 Hydrae is a nearby M Aa = 1.66M ⊙ δ Scuti star with strong astrometric evidence for a close companion in addition to its known M B  = 0.20M ⊙ M dwarf companion at 530 au. Here we report on a VLTI/GRAVITY near-infrared interferometric observation that reveals the close companion to be a M Ab = 1.18M ⊙ star at a projected separation ρ = 168 mas ↔ 8.4 au. This triple system is a potential progenitor for a double white dwarf binary under the dynamical influence of an outer M dwarf companion with a low enough hierarchy for potentially interesting dynamical effects.