Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): V721 CrA and BN CrA have wide and structured disks in the polarised infrared

¹ Alma Mater Studiorum – University of Bologna, Dipartimento di Fisica e Astronomia “Augusto Righi”, Via Gobetti 93/2, 40129 Bologna, Italy
² INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
³ School of Natural Sciences, Centre for Astronomy, University of Galway, Galway, H91 CF50, Ireland
⁴ INAF – Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy
⁵ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁶ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, France
⁷ Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, Milano 20133, Italy
⁸ European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago, Chile
⁹ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
¹⁰ Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
¹¹ Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago, Chile
¹² Millennium Nucleus on Young Exoplanets and their Moons (YEMS)

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Received: 9 July 2025
Accepted: 29 October 2025

Abstract

Context. The environment within which stars form and evolve can play a crucial role in shaping their surrounding protoplanetary disks. This is the reason why homogeneous analyses of protoplanetary disks around young stars in the same star-forming region has become of great relevance in recent years.

Aims. We present near-infrared scattered-light observations of the disks around two stars of the Corona Australis star-forming region, V721 CrA and BN CrA, obtained with VLT/SPHERE in the H band, as part of the DESTINYS large programme. Our objective is to analyse the morphology of these disks and highlight their main properties.

Methods. We adopted an analytical axisymmetric disk model to fit the observations and performed a regression on key disk parameters, namely the dust mass, the height profile, and the inclination. We used RADMC-3D code to produce synthetic observations of the analytical models, with full polarised scattering treatment.

Results. Both stars show resolved and extended disks with substructures in the near-IR. The disk of V721 CrA is vertically thicker, radially smaller (∼120 au), and brighter than that of BN CrA (∼190 au). It also shows spiral arms in the inner regions. The disk of BN CrA shows a dark circular lane, which could be either an intrinsic dust gap or a self-cast shadow, and a brightness enhancement along the disk minor axis. Both disks are compatible with the evolutionary stage of their parent subgroup within the CrA region: V721 CrA belongs to the on-cloud part of CrA, which is dustier, denser, and younger, whereas BN CrA is found on the outskirts of the older off-cloud group.