Protoplanetary disk insights from the first ERIS/vAPP survey at 4 μm

¹ INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
² Università di Firenze, Dipartimento di Fisica e Astronomia, Via Giovanni Sansone 1, 50019 Sesto Fiorentino FI, Italy
³ Alma Mater Studiorum, Università di Bologna, Dipartimento di Fisica e Astronomia (DIFA), Via Gobetti 93/2, 40129 Bologna, Italy
⁴ INAF – Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy
⁵ Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile
⁶ Millennium Nucleus on Young Exoplanets and their Moons (YEMS), Santiago, Chile
⁷ INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁸ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁹ Dipartimento di Fisica, Università degli Studi di Milano, Milano, Italy
¹⁰ European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
¹¹ INAF–Turin Astrophysical Observatory, 10025 Pino Torinese (TO), Italy
¹² INAF-Osservatorio Astronomico di Roma, 00078 Monte Porzio Catone (RM), Italy
¹³ ADONI, INAF ADaptive Optics National laboratory of Italy, Italy
¹⁴ Department of Physics, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome, Italy

^★ Corresponding author: francesco.maio@inaf.it

Received: 3 January 2025
Accepted: 16 April 2025

Abstract

Aims. We present high-contrast imaging observations of seven protoplanetary disks at 4 μm using the Enhanced Resolution Imager and Spectrograph (ERIS) on the Very Large Telescope. This study focuses on detecting scattered light from micron-sized dust particles and assessing the potential of the grating vector Apodizing Phase Plat (gvAPP) coronagraph for disk and planet characterization.

Methods. Observations were performed in pupil-stabilized mode with the vAPP coronagraph. Data were reduced using reference differential imaging and angular differential imaging techniques, incorporating principal component analysis for point-source detection. Contrast curves and detection limits were computed for planetary companions and disk features.

Results. The infrared disk signal was resolved in all systems, with first-time 4 μm detections around AS 209 and Elias 2-24, revealing mostly axisymmetric structures extending up to 60 au. Two gaps were detected in the radial profiles of TW Hya (22 au, 35 au) and AS 209 (50 au, 100 au). For Elias 2-24, scattered light emission matched ALMA observations of inner disk structures, marking their first mid-infrared detection. In the case of HD 100546, the vAPP uncovered flared disk structures and faint spiral arms consistent with previous observations. HD 163296 shows a bright inner dust ring, confirming disk asymmetries and features, but we did not detect any planet candidate within the achieved contrast limits. The disk around PDS 70 exhibits clear features, with faint structures detected within the cavity. The observations achieved contrasts enabling the detection of planets down to 800 K, but no companions were detected, implying either low-mass planets, cooler formation scenarios, or a large dust extinction of A_V ≳ 20 mag.

Conclusions. The vAPP performed robustly for imaging structures in protoplanetary disks at 4 μm, providing critical insights into disk morphology and constraints on planet formation processes. No planetary-mass companions with temperatures >1000 K are present in our sample.