Multi-band infrared imaging reveals dusty spiral arcs around the binary B[e] star 3 Puppis

¹ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Boulevard de l’Observatoire, CS 34229, 06304 Nice cedex 4, France
² European Southern Observatory, Alonso de Córdova, 3107 Vitacura, Santiago, Chile
³ ONERA/DEMR, Université de Toulouse, 31055 Toulouse, France
⁴ Department of Physics & Astronomy, University of Southampton, Southampton SO17 1BJ, UK
⁵ Institute for Astronomy (IfA), University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
⁶ HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Observatory, MTA Centre of Excellence, Konkoly Thege Miklós út 15–17, 1121 Budapest, Hungary
⁷ Institute of Physics and Astronomy, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
⁸ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁹ NASA Goddard Space Flight Center, Astrophysics Division, Greenbelt, MD 20771, USA
¹⁰ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹¹ SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
¹² Center for Astrophysics Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
¹³ Max Planck Institute for Radio Astronomy, Auf dem Hügel 69, 53121 Bonn, Germany
¹⁴ Institute of Theoretical Physics and Astrophysics, University of Kiel, Leibnizstraße 15, 24118, Kiel, Germany

^★ Corresponding author: margaux.abello@oca.eu

Received: 26 July 2025
Accepted: 24 October 2025

Abstract

Context. The star 3 Puppis is the brightest known to exhibit the B[e] phenomenon. Although recent studies have classified this A-type star within the supergiant group, the influence of its binary nature on the circumstellar environment (CE) remains difficult to model. Aims. To resolve its dusty regions at angular scales of 5-10 milliarcseconds (mas), we conducted high angular resolution interferometric observations with the mid-infrared beam combiner VLTI/MATISSE across the 3-12 μm wavelength range.

Methods. Since the (u, v) coverage enables image reconstruction, we present an innovative statistical interferometric imaging technique based on the MiRA software to produce averaged images. Applied to MATISSE data, this systematic approach facilitates the selection of an optimal set of reconstructions, improving the robustness and fidelity of the recovered features. We also applied SPARCO, an independent imaging tool well suited to systems with a bright central source surrounded by a fainter and extended CE.

Results. The images obtained with both tools in the L, M, and N spectral bands show good agreement and clearly reveal an asymmetric elongated structure located at ∼17 mas (∼10 au at 631 pc) to the south-east of the image centre, with a density contrast of ∼20%. A second asymmetry to the north-west and a skewed inner rim are also detected. Simple geometric modelling, inspired by the reconstructed images, provides quantitative constraints on the morphology, position, and flux contribution of the CE and its asymmetries.

Conclusions. Our final MATISSE images are consistent with previous VLTI observations but also reveal a more complex CE with large-scale clumps in the south-east and north-west disc regions of 3 Puppis. Finally, based on a hydrodynamic simulation, we conclude that the tidal spiral wake perturbations driven by the central binary, which are dynamically excited at Lindblad resonances within the circumbinary disc, provide the best interpretation for the radial extent and curvature of the elongated structures observed across all bands.