3-D selection of 167 sub-stellar companions to nearby stars

TL;DR

This study analyzes a large sample of stars to identify and characterize sub-stellar companions, revealing their distribution, occurrence rates, and potential for direct imaging, thereby advancing understanding of wide-orbit brown dwarfs and giant planets.

Contribution

It introduces a novel analysis pipeline combining radial velocity, astrometry, and imaging data to detect and characterize sub-stellar companions around nearby stars.

Findings

Identified 167 cold giants and 68 other companions using combined data.

Estimated a 1.3% minimum occurrence rate of wide-orbit brown dwarfs.

Discovered nine systems previously directly imaged and many observable with current facilities.

Abstract

We analyze 5108 AFGKM stars with at least five high precision radial velocity points as well as Gaia and Hipparcos astrometric data utilizing a novel pipeline developed in previous work. We find 914 radial velocity signals with periods longer than 1000\,d. Around these signals, 167 cold giants and 68 other types of companions are identified by combined analyses of radial velocity, astrometry, and imaging data. Without correcting for detection bias, we estimate the minimum occurrence rate of the wide-orbit brown dwarfs to be 1.3\%, and find a significant brown dwarf valley around 40 $M_{\rm Jup}$. We also find a power-law distribution in the host binary fraction beyond 3 au similar to that found for single stars, indicating no preference of multiplicity for brown dwarfs. Our work also reveals nine sub-stellar systems (GJ 234 B, GJ 494 B, HD 13724 b, HD 182488 b, HD 39060 b and c, HD 4113 C, HD 42581 d, HD 7449 B, and HD 984 b) that have previously been directly imaged, and many others that are observable at existing facilities. Depending on their ages we estimate that an additional 10-57 sub-stellar objects within our sample can be detected with current imaging facilities, extending the imaged cold (or old) giants by an order of magnitude.