Discovery of Seven Companions to Intermediate-mass Stars with Extreme Mass Ratios in the Scorpius–Centaurus Association

Abstract

We report the detection of seven low-mass companions to intermediate-mass stars (SpT B/A/F; ~ 1.5–4.5 M_⊙) in the Scorpius–Centaurus (Sco–Cen) Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts ΔL' ≈ 4–6, corresponding to masses as low as ~20 M_(Jup) and mass ratios of q ≈ 0.01–0.08, depending on the assumed age of the target stars. With projected separations ρ ≈ 10–30 AU, our aperture masking detections sample an orbital region previously unprobed by conventional adaptive optics imaging of intermediate-mass Sco–Cen stars covering much larger orbital radii (~30–3000 AU). At such orbital separations, these objects resemble higher-mass versions of the directly imaged planetary mass companions to the 10–30 Myr, intermediate-mass stars HR 8799, β Pictoris, and HD 95086. These newly discovered companions span the brown dwarf desert, and their masses and orbital radii provide a new constraint on models of the formation of low-mass stellar and substellar companions to intermediate-mass stars.

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