Constraining masses and separations of unseen companions to five accelerating nearby stars^★

¹ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, Padova 35122, Italy
e-mail: dino.mesa@inaf.it
² School of Physical Sciences, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
³ INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134 Palermo, Italy
⁴ Jesus College, University of Cambridge, Jesus Lane, Cambridge CB5 8BL, UK
⁵ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA, UK
⁶ LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France
⁷ Max-Planck-Institut für Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁸ Department of Astronomy, Stockholm University, AlbaNova, University Center, 109 91 Stockholm, Sweden
⁹ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
¹⁰ CRAL, UMR 5574, CNRS, Université de Lyon, Ecole Normale Superieure de Lyon, 46 Allée d’Italie, 69364 Lyon Cedex 07, France
¹¹ Observatoire Astronomique de l’Université de Geneve, 51 Ch. des Maillettes, 1290 Versoix, Switzerland
¹² Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
¹³ Nucleo de Astronomia, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
¹⁴ Escuela de Ingenieria Industrial, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
¹⁵ SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
¹⁶ Centre for Exoplanet Science, University of Edinburgh, Edinburgh, UK
¹⁷ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁸ 5Center for Space and Habitability, University of Bern, 3012 Bern, Switzerland
¹⁹ Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
²⁰ Space Telescope Science Institute, Baltimore 21218, MD, USA
²¹ Geneva Observatory, University of Geneva, Chemin des Maillettes 51, 1290 Versoix, Switzerland
²² University of Côte d’Azur, Côte d’Azur Observatory, CNRS, Lagrange Laboratory, France
²³ STAR Institute, Université de Liège, Allee du Six Août 19c, 4000 Liège, Belgium
²⁴ ESO Vitacura, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile
²⁵ Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany

Received: 16 May 2022
Accepted: 24 June 2022

Abstract

Aims. In this work, we aim to constrain the masses and separations of potential substellar companions to five accelerating stars (HIP 1481, HIP 88399, HIP 96334, HIP 30314, and HIP 116063) using multiple data sets acquired with different techniques.

Methods. Our targets were originally observed as part of the SPHERE/SHINE survey, and radial velocity (RV) archive data were also available for four of the five objects. No companions were originally detected in any of these data sets, but the presence of significant proper motion anomalies (PMas) for all the stars strongly suggested the presence of a companion. Combining the information from the PMas with the limits derived from the RV and SPHERE data, we were able to put constraints on the characteristics of the unseen companions.

Results. Our analysis led to relatively strong constraints for both HIP 1481 and HIP 88399, narrowing down the companion masses to 2–5 M_Jup and 3–5 M_Jup and separations within 2–15 au and 3–9 au, respectively. Because of the large age uncertainties for HIP 96334, the poor observing conditions for the SPHERE epochs of HIP 30314, and the lack of RV data for HIP 116063, the results for these targets were not as well defined, but we were still able to constrain the properties of the putative companions within a reasonable confidence level.

Conclusions. For all five targets, our analysis reveals that the companions responsible for the PMa signal would be well within reach for future instruments planned for the ELT (e.g., MICADO), which would easily achieve the required contrast and angular resolution. Our results therefore represent yet another confirmation of the power of multi-technique approaches for both the discovery and characterisation of planetary systems.