Revealing asymmetrical dust distribution in the inner regions of HD 141569

Abstract

We obtained polarimetric differential imaging of a gas-rich debris disk around HD 141569A with SPHERE in the H-band to compare the scattering properties of the innermost ring at 44 au with former observations in total intensity with the same instrument. In polarimetric imaging, we observed that the intensity of the ring peaks in the south-east, mostly in the forward direction, whereas in total intensity imaging, the ring is detected only at the south. This noticeable characteristic suggests a non-uniform dust density in the ring. We implemented a density function varying azimuthally along the ring and generated synthetic images both in polarimetry and in total intensity, which are then compared to the actual data. We find that the dust density peaks in the south-west at an azimuthal angle of $220^{\circ }\sim 238^{\circ }$ with a rather broad width of $61^{\circ }\sim 127^{\circ }$. Although there are still uncertainties that remain in the determination of the anisotropic scattering factor, the implementation of an azimuthal density variation to fit the data proved to be robust. Upon elaborating on the origin of this dust density distribution, we conclude that it could be the result of a massive collision when we account for the effect of the high gas mass that is present in the system on the dynamics of grains. Using the outcome of this modelization, we further measured the polarized scattering phase function for the observed scattering angle between 33${}^{\circ }$ and 147${}^{\circ }$ as well as the spectral reflectance of the southern part of the ring between 0.98 $\mu$m and 2.1 $\mu$m. We tentatively derived the grain properties by comparing these quantities with MCFOST models and assuming Mie scattering. Our preliminary interpretation indicates a mixture of porous sub-micron sized astro-silicate and carbonaceous grains.

21 pages, 18 figures, Accepted for publication in Astronomy & Astrophysics journal

References in corpus (24)

• The Gemini Planet Imager: First Light
• Monte Carlo radiative transfer in protoplanetary disks
• Performance of the VLT Planet Finder SPHERE II. Data analysis and Results for IFS in laboratory
• Detection of exocometary CO within the 440 Myr-old Fomalhaut belt: a similar CO+CO${}_2$ ice abundance in exocomets and Solar System comets
• Debris from giant impacts between planetary embryos at large orbital radii
• Near-infrared scattered light properties of the HR4796A dust ring: a measured scattering phase function from 13.6deg to 166.6deg
• 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
• SPHERE IRDIS and IFS astrometric strategy and calibration
• Blobs, spiral arms, and a possible planet around HD 169142
• Gap Clearing by Planets in a Collisional Debris Disk
• Optical polarized phase function of the HR\,4796A dust ring
• Experimental phase function and degree of linear polarization of cometary dust analogs
• Investigating the flyby scenario for the HD 141569 system
• Population synthesis of exocometary gas around A stars
• ALMA Detection of Extended Millimeter Halos in the HD 32297 and HD 61005 Debris Disks
• The HIP 79977 debris disk in polarized light
• Characterization of the inner disk around HD 141569 A from Keck/NIRC2 L-band vortex coronagraphy
• Fomalhaut b as a Dust Cloud: Frequent Collisions within the Fomalhaut Disk
• Signatures of massive collisions in debris discs
• The challenge of measuring the phase function of debris disks. Application to HR\,4796
• Investigating the presence of two belts in the HD 15115 system
• Tidal disruption versus planetesimal collisions as possible origins for the dispersing dust cloud around Fomalhaut
• Imaging the 44 AU Kuiper Belt-analogue debris ring around HD 141569A with GPI polarimetry

Cited by in corpus (8)

• The JWST Early Release Science Program for the Direct Imaging & Spectroscopy of Exoplanetary Systems
• Reference-star differential imaging on SPHERE/IRDIS
• Morphology of the gas-rich debris disk around HD 121617 with SPHERE observations in polarized light
• Color measurements of the polarized light scattered by the dust in protoplanetary disks
• Multi-band reflectance and shadowing of RX J1604.3-2130 protoplanetary disk in scattered light
• Discovery of carbon monoxide emission from five debris disks around young A-type stars
• A Multiband Study of the HR 4796A Disk in the Optical Using MagAO-X
• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) XI: Gas-dust interactions and radial offsets between micron and millimetre-sized grains