Seven Stellar Companions Span 'Brown Dwarf Desert'

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

Authors:

Hinkley et al

Abstract:

We report the detection of seven low mass companions to intermediate-mass stars (SpT B/A/F; M≈1.5-4.5 solar masses) in the Scorpius-Centaurus Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts ΔL′≈4-6, corresponding to masses as low as ∼20 Jupiter masses 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 Scorpius-Centaurus 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 HD95086. 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.