The protoplanetary system HD 100546 in H$\alpha$ polarized light from SPHERE/ZIMPOL. A bar-like structure across the disk gap?

Abstract

HD 100546 is one of the few known pre-main-sequence stars that may host a planetary system in its disk. We analyze new VLT/SPHERE/ZIMPOL polarimetric images of HD 100546 with filters in H$\alpha$ and the adjacent continuum. We have probed the disk gap and the surface layers of the outer disk, covering a region < 500 mas (< 55 au at 109 pc) from the star, at an angular resolution of ~ 20 mas. Our data show an asymmetry: the SE and NW regions of the outer disk are more polarized than the SW and NE. This can be explained from a preferential scattering angle close to 90${}^o$, consistent with previous polarization images. The outer disk extends from 13 $\pm$ 2 to 45 $\pm$ 9 au, with a position angle and inclination of 137 $\pm$ 5${}^o$ and 44 $\pm$ 8${}^o$. The comparison with previous estimates suggests that the disk inclination could increase with the stellocentric distance, although the different measurements are still consistent within the error bars. In addition, no direct signature of the innermost candidate companion is detected from polarimetry, confirming recent results based on intensity imagery. We set an upper limit to its mass accretion rate < 10${}^{-8}$ M${}_{\odot }$/yr for a sub-stellar mass of 15M${}_{Jup}$. Finally, we report the first detection (> 3$\sigma$) of a ~ 20 au bar-like structure that crosses the gap through the central region of HD 100546. It is tentatively suggested that the bar could be dust dragged by infalling gas that radially flows from the outer disk. This could represent an exceptional case in which a small-scale radial inflow is observed in a single system. If this scenario is confirmed, it could explain the presence of atomic gas in the inner disk that would otherwise accrete on to the central star on a timescale of a few months/years, as previously indicated from spectro-interferometric data, and could be related with additional (undetected) planets.

arXiv comment8 pages, 7 figures. Accepted in A&A

References in corpus (66)

• Interstellar Dust Grains
• Disk Frequencies and Lifetimes in Young Clusters
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
• Disk Accretion Onto High-Mass Planets
• UV excess measures of accretion onto young very low-mass stars and brown dwarfs
• Observations of gas flows inside a protoplanetary gap
• Mass Flow and Accretion through gaps in Accretion Discs
• Accreting Protoplanets in the LkCa 15 Transition Disk
• Gas Flow Across Gaps in Protoplanetary Disks
• A spectroscopic survey of Herbig Ae/Be stars with X-Shooter I: Stellar parameters and accretion rates
• A young protoplanet candidate embedded in the circumstellar disk of HD100546
• The origin of crystalline silicates in the Herbig Be star HD100546 and in comet Hale-Bopp
• A Likely Close-In Low-Mass Stellar Companion to the Transitional Disk Star HD 142527
• [O I] 6300A emission in Herbig Ae/Be systems: signature of Keplerian rotation
• Accreting Circumplanetary Disks: Observational Signatures
• A Multi-Ringed, Modestly-Inclined Protoplanetary Disk around AA Tau
• Resolving the HD 100546 Protoplanetary System with the Gemini Planet Imager: Evidence for Multiple Forming, Accreting Planets
• The complex structure of the disk around HD100546: the inner few astronomical units
• Discovery of H-alpha Emission from the Close Companion Inside the Gap of Transitional Disk HD142527
• ALMA hints at the presence of two companions in the disk around HD 100546
• GASPS - a Herschel survey of gas and dust in Protoplanetary Disks: Summary and Initial Statistics
• HST/NICMOS2 coronagraphic observations of the circumstellar environment of three old PMS stars: HD 100546, SAO 206462 and MWC 480
• Accretion onto Planetary Mass Companions of Low-Mass Young Stars
• Recovery of the Candidate Protoplanet HD 100546 b with Gemini/NICI and Detection of Additional (Planet-Induced?) Disk Structure at Small Separations
• The SPHERE view of the planet-forming disk around HD100546
• Tracing the inner edge of the disk around HD 100546 with Ro-vibrational CO Emission Lines
• Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO
• VLT/NACO Polarimetric Differential Imaging of HD100546 - Disk Structure and Dust Grain Properties between 10-140 AU
• Resolving the disk rotation of HD 97048 and HD 100546 in the [O I] 6300A line: evidence for a giant planet orbiting HD 100546
• Evidence for CO depletion in the inner regions of gas-rich protoplanetary disks
• Relating jet structure to photometric variability: the Herbig Ae star HD 163296
• An M-dwarf star in the transition disk of Herbig HD 142527; Physical parameters and orbital elements
• Spectroscopic Confirmation of Young Planetary-Mass Companions on Wide Orbits
• The Case of AB Aurigae's Disk in Polarized Light: Is There Truly a Gap?
• NIR Spectroscopy of the HAeBe Star HD 100546: III. Further Evidence of an Orbiting Companion?
• HD100546 Multi-Epoch Scattered-Light Observations
• Direct Imaging of Bridged Twin Protoplanetary Disks in a Young Multiple Star
• Fast Radial Flows in Transition Disk Holes
• Constraining the structure of the planet-forming region in the disk of the Herbig Be star HD 100546
• An Optical/near-infrared investigation of HD 100546 b with the Gemini Planet Imager and MagAO
• Non-azimuthal linear polarization in protoplanetary disks
• Multiple spiral patterns in the transitional disk of HD 100546
• Detection of CH+ emission from the disc around HD100546
• Sequential planet formation in the HD 100546 protoplanetary disk?
• Planet or Brown Dwarf? Inferring the Companion Mass in HD 100546 from the Wall Shape using Mid-Infrared Interferometry
• A spectroscopic survey of Herbig Ae/Be stars with X-Shooter II: Accretion diagnostic lines
• CO emission tracing a warp or radial flow within $\lesssim$ 100 au in the HD 100546 protoplanetary disk
• Warm molecular gas and kinematics in the disc around HD 100546
• The dust disk and companion of the nearby AGB star L2 Puppis - SPHERE/ZIMPOL polarimetric imaging at visible wavelengths
• Resolved images of the protoplanetary disk around HD 100546 with ALMA
• A Resolved Circumstellar Disk around the Herbig Ae Star HD 100546 in the Thermal Infrared
• Resolving HD 100546 disc in the mid-infrared: Small inner disc and asymmetry near the gap
• High-resolution Br-gamma spectro-interferometry of the transitional Herbig Ae/Be star HD 100546: a Keplerian gaseous disc inside the inner rim
• On the origin of the correlations between the accretion luminosity and emission line luminosities in pre-main sequence stars
• Circumbinary Gas Accretion onto a Central Binary: Infrared Molecular Hydrogen Emission from GG Tau A
• High-Resolution Near Infrared Spectroscopy of HD 100546: II. Analysis of variable rovibrational CO emission lines
• High resolution imaging of the GG Tau system at 267 GHz
• The Warped Circumstellar Disk of HD100546
• CO ro-vibrational lines in HD100546: A search for disc asymmetries and the role of fluorescence
• The compact H$\alpha$ emitting regions of the Herbig Ae/Be stars HD 179218 and HD 141569 from CHARA spectro-interferometry
• Possible Signatures of Magnetospheric Accretion onto Young Giant Planets
• High-Resolution Near Infrared Spectroscopy of HD 100546: I. Analysis of Asymmetric Ro-Vibrational OH Emission Lines
• The close circumstellar environment of Betelgeuse - III. SPHERE/ZIMPOL visible polarimetry of the inner envelope and photosphere
• A "Rosetta Stone" for protoplanetary disks: The synergy of multi-wavelength observations
• Resolved observations of transition disks

Cited by in corpus (15)

• An inner warp in the DoAr 44 T Tauri transition disk
• Spiral Arms in Disks: Planets or Gravitational Instability?
• A search for accreting young companions embedded in circumstellar disks: High-contrast H$\alpha$ imaging with VLT/SPHERE
• CO emission tracing a warp or radial flow within $\lesssim$ 100 au in the HD 100546 protoplanetary disk
• The widest H$\alpha$ survey of accreting protoplanets around nearby transition disks
• A family portrait of disk inner rims around Herbig Ae/Be stars: Hunting for warps, rings, self shadowing, and misalignments in the inner astronomical units
• Herbig Stars: A Quarter Century of Progress
• Spectro-astrometry of the pre-transitional star LkCa 15 does not reveal an accreting planet but extended H$\alpha$ emission
• ISPY-NACO Imaging Survey for Planets around Young stars. The demographics of forming planets embedded in protoplanetary disks
• Asymmetric mid-plane gas in ALMA images of HD~100546
• Searching for H${}_{\alpha }$ emitting sources around MWC758: SPHERE/ZIMPOL high-contrast imaging
• Gas accretion within the dust cavity in AB Aur
• Discovery of a jet from the single HAe/Be star HD 100546
• Spatially resolving polycyclic aromatic hydrocarbons in Herbig Ae disks with VISIR-NEAR at the VLT
• New Mid-Infrared Imaging Constraints on Companions and Protoplanetary Disks around six Young Stars