Second-generation protoplanetary discs around evolved binaries: a high-resolution polarimetric view with SPHERE/IRDIS

Abstract

Binary post-asymptotic giant branch (post-AGB) stars are products of a poorly understood binary interaction process that occurs during the AGB phase. These systems comprise of a post-AGB primary star, a main-sequence secondary companion and a stable circumbinary disc. Studying the structure and properties of these circumbinary discs is crucial for gaining insight into the binary interaction process that governs post-AGB binaries as well as comprehending the disc's creation, evolution, and its interaction with the post-AGB binary system. We aim to use near-infrared polarimetric imaging to investigate the morphology and potential substructures of circumbinary discs around eight representative post-AGB binary stars. To achieve this, we performed polarimetric differential imaging in H and Y bands using the high-angular resolution capabilities of the European Southern Observatory-Very Large Telescope/SPHERE-Infra-Red Dual-beam Imaging and Spectroscopy instrument. We resolved the extended circumbinary disc structure for a diverse sample of eight post-AGB binary systems. Our analysis provided the first estimates of the disc scale-height for two of the systems: IW Car and IRAS 15469-5311. We also investigated the morphological differences between the full discs (with the inner rim at the dust sublimation radius) and transition discs (which are expected to have larger inner cavities), as well as similarities to protoplanetary disks around young stellar objects. We found that the transition discs displayed a more intricate and asymmetric configuration. Surprisingly, no correlation was found between the over-resolved flux in near-IR interferometric data and the polarimetric observations, suggesting that scattering of light on the disc surface may not be the primary cause of the observed over-resolved flux component.

References in corpus (28)

• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Keplerian discs around post-AGB stars: a common phenomenon?
• The polarimetric imaging mode of VLT/SPHERE/IRDIS II: Characterization and correction of instrumental polarization effects
• The polarimetric imaging mode of VLT/SPHERE/IRDIS I: Description, data reduction and observing strategy
• Optically visible post-AGB/RGB stars and young stellar objects in the Small Magellanic Cloud: candidate selection, spectral energy distributions and spectroscopic examination
• Multiple rings in the transition disk and companion candidates around RXJ1615.3-3255. High contrast imaging with VLT/SPHERE
• Establishing binarity amongst Galactic RV Tauri stars with a disc
• Fingerprints of giant planets in the composition of solar twins
• A population of transition disks around evolved stars: Fingerprints of planets? Catalog of disks surrounding Galactic post-AGB binaries
• Defining the instability strip of pulsating post-AGB binary stars from ASAS and NSVS photometry
• Detection of Keplerian dynamics in a disk around the post-AGB star AC Her
• A mid-IR interferometric survey with MIDI/VLTI: resolving the second-generation protoplanetary disks around post-AGB binaries
• A second post-AGB nebula that contains gas in rotation and in expansion: ALMA maps of IW Car
• First detection of surface magnetic fields in Post-AGB stars : the cases of U Monocerotis and R Scuti
• The evolved circumbinary disk of AC Her: a radiative transfer, interferometric and mineralogical study
• HD142527: Quantitative disk polarimetry with SPHERE
• AGB dust and gas ejecta in extremely metal-poor environments
• The structure of jets launched from post-AGB binary systems
• Keplerian disks and outflows in post-AGB stars: AC Herculis, 89 Herculis, IRAS 19125+0343, and R Scuti
• Infrared High-Resolution Spectroscopy of Post-AGB Circumstellar Disks. I. HR 4049 - The Winnowing Flow Observed?
• Amplitude variations of modulated RV Tauri stars support the dust obscuration model of the RVb phenomenon
• Resolved imaging of the AR Puppis circumbinary disk
• Physical properties of galactic RV Tauri stars from Gaia DR2 data
• Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc
• Multiwavelength Observations of the RV Tauri Variable System U Monocerotis: Long-Term Variability Phenomena That Can Be Explained by Binary Interactions with a Circumbinary Disk
• Nano-diamonds in proto-planetary discs: Life on the edge
• The Gas-Rich Circumbinary Disk of HR 4049. II: A Detailed Study of the Near-Infrared Spectrum
• VLTI images of circumbinary disks around evolved stars