Resolving the planet-hosting inner regions of the LkCa 15 disk

Abstract

LkCa 15 hosts a pre-transitional disk as well as at least one accreting protoplanet orbiting in its gap. Previous disk observations have focused mainly on the outer disk, which is cleared inward of ~50 au. The planet candidates, on the other hand, reside at orbital radii around 15 au, where disk observations have been unreliable until recently. Here we present new J-band imaging polarimetry of LkCa 15 with SPHERE IRDIS, yielding the most accurate and detailed scattered-light images of the disk to date down to the planet-hosting inner regions. We find what appear to be persistent asymmetric structures in the scattering material at the location of the planet candidates, which could be responsible at least for parts of the signals measured with sparse-aperture masking. These images further allow us to trace the gap edge in scattered light at all position angles and search the inner and outer disks for morphological substructure. The outer disk appears smooth with slight azimuthal variations in polarized surface brightness, which may be due to shadowing from the inner disk or a two-peaked polarized phase function. We find that the near-side gap edge revealed by polarimetry matches the sharp crescent seen in previous ADI imaging very well. Finally, the ratio of polarized disk to stellar flux is more than six times larger in J-band than in the RI bands.

6 pages, 4 figures, 1 table; accepted for publication in ApJ Letters

References in corpus (6)

• On the Diversity of the Taurus Transitional Disks: UX Tau A & Lk Ca 15
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Reconnaissance of the HR 8799 Exosolar System II: Astrometry and Orbital Motion
• Searching for circumplanetary disks around LkCa 15
• HD100546 Multi-Epoch Scattered-Light Observations
• GPI PSF subtraction with TLOCI: the next evolution in exoplanet/disk high-contrast imaging

Cited by in corpus (36)

• Population-Level Eccentricity Distributions of Imaged Exoplanets and Brown Dwarf Companions: Dynamical Evidence for Distinct Formation Channels
• On the diversity of asymmetries in gapped protoplanetary disks
• No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals
• Hints for icy pebble migration feeding an oxygen-rich chemistry in the inner planet-forming region of disks
• Exploring dust around HD142527 down to 0.025" / 4au using SPHERE/ZIMPOL
• Perturbers: SPHERE detection limits to planetary-mass companions in protoplanetary disks
• Annular substructures in the transition disks around LkCa 15 and J1610
• Spatial segregation of dust grains in transition disks. SPHERE observations of 2MASS J16083070-3828268 and RXJ1852.3-3700
• The widest H$\alpha$ survey of accreting protoplanets around nearby transition disks
• Separating extended disc features from the protoplanet in PDS 70 using VLT/SINFONI
• A gap in HD 92945's broad planetesimal disc revealed by ALMA
• Gas temperature structure across transition disk cavities
• Transition disks: the observational revolution from SEDs to imaging
• Kinematics and brightness temperatures of transition discs -- A survey of gas substructures as seen with ALMA
• ALMA Detection of Dust Trapping around Lagrangian Points in the LkCa 15 Disk
• Protoplanetary disks in $K_s$-band total intensity and polarized light
• Mapping Protoplanetary Disk Vertical Structure with CO Isotopologue Line Emission
• Binaries among low-mass stars in nearby young moving groups
• Searching for proto-planets with MUSE
• The Giant Accreting Protoplanet Survey (GAPlanetS) -- Results from a Six Year Campaign to Image Accreting Protoplanets
• Searching for H${}_{\alpha }$-emitting sources in the gaps of five transitional disks. SPHERE/ZIMPOL high-contrast imaging
• Observed polarized scattered light phase functions of planet-forming disks
• A Transient Transit Signature Associated with the Young Star RIK-210
• Constraints on the (re-)orientation of star-disk systems through infall
• Systematic Multi-Epoch Monitoring of LkCa 15: Dynamic Dust Structures on Solar-System Scales
• Disentangling protoplanetary disk gas mass and carbon depletion through combined atomic and molecular tracers
• The Giant Accreting Protoplanet Survey (GAPlanetS): Optimization Techniques for Robust Detections of Protoplanets
• Feasibility of detecting and characterizing embedded low-mass giant planets in gaps in the VIS/NIR wavelength range
• The circumstellar environment of EX Lup: the SPHERE and SINFONI views
• Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Diverse outcomes of binary-disk interactions
• Detection of H$\alpha$ emission from PZ Tel B using SPHERE/ZIMPOL
• Strong H$\alpha$ emission in the young planetary mass companion 2MASS J0249-0557 c
• Color measurements of the polarized light scattered by the dust in protoplanetary disks
• Planet-forming disks and their environment across regions and time from the full NIR census
• Probing inner and outer disk misalignments in transition disks
• Two Rings and a Marginally Resolved, 5 AU, Disk Around LkCa 15 Identified Via Near Infrared Sparse Aperture Masking Interferometry