SIMBAD references

2020ApJ...902L...6W - Astrophys. J., 902, L6-L6 (2020/October-2)

Direct imaging discovery of a young brown dwarf companion to an A2V star.

WAGNER K., APAI D., KASPER M., McCLURE M., ROBBERTO M. and CURRIE T.

Abstract (from CDS):

We present the discovery and spectroscopy of HIP 75056Ab, a companion directly imaged at a very small separation of 0.''125 to an A2V star in the Scorpius-Centaurus OB2 association. Our observations utilized Very Large Telescope/Spectro-Polarimetric High-contrast Exoplanet Research Experiment between 2015 and 2019, enabling low-resolution spectroscopy (0.95-1.65 µm), dual-band imaging (2.1-2.25 µm), and relative astrometry over a four-year baseline. HIP 75056Ab is consistent with spectral types in the range of M6-L2 and Teff ∼ 2000-2600 K. A comparison of the companion's brightness to evolutionary tracks suggests a mass of ∼20-30 MJup. The astrometric measurements are consistent with an orbital semimajor axis of ∼15-45 au and an inclination close to face-on (i <= 35°). In this range of mass and orbital separation, HIP 75056Ab is likely at the low-mass end of the distribution of companions formed via disk instability, although a formation of the companion via core accretion cannot be excluded. The orbital constraints are consistent with the modest eccentricity values predicted by disk instability, a scenario that can be confirmed by further astrometric monitoring. HIP 75056Ab may be utilized as a low-mass atmospheric comparison to older, higher-mass brown dwarfs, and also to young giant planets. Finally, the detection of HIP 75056Ab at 0.''125 represents a milestone in detecting low-mass companions at separations corresponding to the habitable zones of nearby Sun-like stars.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Brown dwarfs - Direct imaging - Exoplanets

Simbad objects: 13

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