* Astronomy

Title: Discovery of Seven Companions to Intermediate Mass Stars with Extreme Mass Ratios in the Scorpius-Centaurus Association
Author: Sasha Hinkley (Exeter), Adam L. Kraus (UT), Michael J. Ireland (ANU), Anthony Cheetham (Sydney), John M. Carpenter (Caltech), Peter Tuthill (Sydney), Sylvestre Lacour (LESIA), Thomas M. Evans (Exeter), Xavier Haubois (LESIA, ESO)

We report the detection of seven low mass companions to intermediate-mass stars (SpT B/A/F; M \approx 1.5-4.5 solar masses) in the Scorpius-Centaurus Association using nonredundant aperture masking interferometry. Our newly detected objects have contrasts Delta L' \approx 4-6, corresponding to masses as low as ~20 Jupiter masses and mass ratios of q \approx 0.01-0.08, depending on the assumed age of the target stars. With projected separations rho \approx 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 (\approx 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, Beta 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.

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