Astronomers from the Astronomical Observatory of Padova and Italy have conducted observations of 25 stars as part of the COPAINS Pilot Survey. They have detected four new brown dwarfs that received designations HIP 21152 B, HIP 29724 B, HD 60584 B and HIP 63734 B. The finding was published in the arXiv pre-print server.
Brown dwarfs are intermediate objects between planets and stars which occupy the mass range between 13 and 80 Jupiter masses. Although many brown dwarfs have been detected to date, such objects orbiting other stars are a rare find.
A team of astronomers led by Mariangela Bonavita reports the detection of four such objects. The discovery was made with a new tool known as Code for Orbital Parametrization of Astrometrically Inferred New Systems (COPAINS). It was part of a pilot survey conducted with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. It is an extreme adaptive optics facility at ESO’s Very Large Telescope (VLT) which employed the COPAINS tool for informed target selection.
Scientists present the results of the COPAINS Survey conducted with SPHERE/VLT. They are searching for sub-stellar companions to stars showing significant proper motion differences (∆µ) between different astrometric catalogs. They observed twenty-five stars and detected ten companions, including four new brown dwarfs which are HIP 21152 B, HIP 29724 B, HD 60584 B and HIP 63734 B.
The newly found brown dwarfs are sub-stellar companions of relatively young stars. The masses of these stars are estimated to be between 1.04 and 1.44 solar masses. HIP 21152 B, HIP 29724 B, HD 60584 B and HIP 63734 B have masses at a level of 0.032, 0.063, 0.028 and 0.012. They are separated from their host stars by 18.3, 6.3, 16.6 and 30 AU. Scientists note that their discovery underlines the ability of COPAINS to constrain the underlying planet and sub-stellar companion population. They added that surveys like COPAINS offer an undeniably efficient selection method. It provided a much higher success rate with a considerably smaller time commitment.