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

TL;DR

This paper reports the discovery of seven low-mass companions to intermediate-mass stars in the Scorpius-Centaurus Association using aperture masking interferometry, revealing objects with extreme mass ratios at intermediate orbital separations.

Contribution

The study presents the first detection of low-mass companions at 10-30 AU around intermediate-mass stars using aperture masking, expanding the understanding of companion demographics in this region.

Findings

Seven low-mass companions detected with contrasts of 4-6 magnitudes.

Companions have masses as low as 20 Jupiter masses and mass ratios of 0.01-0.08.

Detected objects fill the brown dwarf desert at 10-30 AU.

Abstract

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 $\sim$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.