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

We report the detection of seven low-mass companions to intermediate-mass stars (SpT B/A/F; M ∼ 1.5-4.5 M_⊙) in the Scorpius-Centaurus (Sco-Cen) Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts {Δ }L^\prime ≈ 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.

Based on observations made with ESO Telescopes at the La Silla Paranal Observatory Under Program IDs: 0.87.C-0790 and 089.C-0605.