A New Method for Target Selection in Direct Imaging Programs with COPAINS

Abstract

We present COPAINS (Code for Orbital Parametrisation of Astrometrically Inferred New Systems), an innovative tool developed to identify previously undiscovered companions detectable via direct imaging, based on changes in stellar proper motions across multiple astrometric catalogues. This powerful procedure allows for dynamical predictions of the possible masses and separations of unseen companions compatible with observed astrometric trends, marginalised over unknown orbital elements. Validating our approach using well-constrained systems, we found that our tool provides a good indication of the region of the parameter space where undetected secondaries may be located. Comparing the output of the code to the measured or expected sensitivity from various imaging instruments, this in turn enables us to robustly select the most promising targets for direct imaging campaigns searching for low-mass companions. Such an informed selection method promises to reduce the null detection rates from current programs and will significantly increase the current census of wide brown dwarfs and planetary companions to stars, which remain extremely rare in the surveys conducted so far.

15 pages, 10 figures. Accepted for publication in MNRAS

References in corpus (9)

• The Gaia mission
• The Gemini Deep Planet Survey -- GDPS
• The Palomar/Keck Adaptive Optics Survey of Young Solar Analogs: Evidence for a Universal Companion Mass Function
• The Tycho-Gaia astrometric solution. How to get 2.5 million parallaxes with less than one year of Gaia data
• Distances and parallax bias in Gaia DR2
• A novel L-band imaging search for giant planets in the Tucana and Beta Pictoris moving groups
• The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass
• Proper-motion binaries in the Hipparcos Catalogue. Comparison with radial velocity data
• A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

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• Results from The COPAINS Pilot Survey: four new brown dwarfs and a high companion detection rate for accelerating stars
• Frequency of Planets in Binaries
• Surveying Nearby Brown Dwarfs with HGCA: Direct Imaging Discovery of a Faint, High-Mass Brown Dwarf Orbiting HD 176535 A
• VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B
• A new white dwarf companion to the $\Delta \mu$ star GJ 3346
• The McDonald Accelerating Stars Survey (MASS): Architecture of the Ancient Five-Planet Host System Kepler-444
• SCExAO/CHARIS Direct Imaging of A Low-Mass Companion At A Saturn-Like Separation from an Accelerating Young A7 Star
• High-contrast detection of exoplanets with a kernel-nuller at the VLTI
• An optimised survey strategy for the ERIS/NIX imager: searching for young giant exoplanets and very low mass brown dwarfs using the K-peak custom photometric filter
• htof: A new open-source tool for analyzing Hipparcos, Gaia, and future astrometric missions