Binary asteroid candidates in Gaia DR3 astrometry^★

¹ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice Cedex 4, France
e-mail: luana.liberato@oca.eu
² São Paulo State University, Grupo de Dinâmica Orbital e Planetologia, CEP 12516-410, Guaratinguetá, SP, Brazil
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 15, Cambridge, MA 02138, USA
⁴ LESIA, Paris Observatory, PSL University, CNRS, Sorbonne University, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
⁵ Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland
⁶ Polytechnic Institute of Advanced Sciences-IPSA, 63 Boulevard de Brandebourg, 94200 Ivry-sur-Seine, France
⁷ Institute of Celestial Mechanics and Ephemeris Calculation (IMCCE), Paris Observatory, PSL Research University, CNRS, Sorbonne University, UPMC Univ Paris 06, Univ. Lille, 77 Av. Denfert-Rochereau, 75014 Paris, France
⁸ Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías (IUFACyT), Universidad de Alicante, Ctra. San Vicente del Raspeig s/n, 03690 San Vicente del Raspeig, Alicante, Spain

Received: 28 December 2023
Accepted: 10 May 2024

Abstract

Context. Asteroids with companions constitute an excellent sample for studying the collisional and dynamical evolution of minor planets. The currently known binary population were discovered by different complementary techniques that produce, for the moment, a strongly biased distribution, especially in a range of intermediate asteroid sizes (≈2–100 km) where both mutual photometric events and high-resolution adaptive optic imaging are poorly efficient.

Aims. A totally independent technique of binary asteroid discovery, based on astrometry, can help to reveal new binary systems and populate a range of sizes and separations that remain nearly unexplored.

Methods. In this work, we describe a dedicated period detection method and its results for the Gaia DR3 data set. This method looks for the presence of a periodic signature in the orbit post-fit residuals.

Results. After conservative filtering and validation based on statistical and physical criteria, we are able to present a first sample of astrometric binary candidates, to be confirmed by other observation techniques such as photometric light curves and stellar occultations.