Pre-transitional disks are protoplanetary disks with a gapped disk structure, potentially indicating the presence of young planets in these systems. In order to explore the structure of these objects and their gap-opening mechanism, we observed the pre-transitional disk V1247 Orionis using the Very Large Telescope Interferometer, the Keck Interferometer, Keck-II, Gemini South, and IRTF. This allows us spatially resolve the AU-scale disk structure from near-to mid-infrared wavelengths (1.5 to 13 µm), tracing material at different temperatures and over a wide range of stellocentric radii. Our observations reveal a narrow, optically-thick inner-disk component (located at 0.18 AU from the star) that is separated from the optically thick outer disk (radii 46 AU), providing unambiguous evidence for the existence of a gap in this pre-transitional disk. Surprisingly, we find that the gap region is filled with significant amounts of optically thin material with a carbon-dominated dust mineralogy. The presence of this optically thin gap material cannot be deduced solely from the spectral energy distribution, yet it is the dominant contributor at mid-infrared wavelengths. Furthermore, using Keck/NIRC2 aperture masking observations in the H, K ′ , and L ′ band, we detect asymmetries in the brightness distribution on scales of ∼ 15-40 AU, i.e. within the gap region. The detected asymmetries are highly significant, yet their amplitude and direction changes with wavelength, which is not consistent with a companion interpretation but indicates an inhomogeneous distribution of the gap material. We interpret this as strong evidence for the presence of complex density structures, possibly reflecting the dynamical interaction of the disk material with sub-stellar mass bodies that are responsible for the gap clearing.

We present near-IR and far-UV observations of the pre-transitional (gapped) disk in HD 169142 using NASA's Infrared Telescope Facility and Hubble Space Telescope. -2 -The combination of our data along with existing data sets into the broadband spectral energy distribution reveals variability of up to 45% between ∼1.5-10 µm over a maximum timescale of 10 years. All observations known to us separate into two distinct states corresponding to a high near-IR state in the pre-2000 epoch and a low state in the post-2000 epoch, indicating activity within the 1 AU region of the disk. Through analysis of the Pa β and Br γ lines in our data we derive a mass accretion rate in May 2013 ofṀ ≈ (1.5 -2.7) x 10 −9 M yr −1 . We present a theoretical modeling analysis of the disk in HD 169142 using Monte-Carlo radiative transfer simulation software to explore the conditions and perhaps signs of planetary formation in our collection of 24 years of observations. We find that shifting the outer edge (r ≈ 0.3 AU) of the inner disk by 0.05 AU toward the star (in simulation of accretion and/or sculpting by forming planets) successfully reproduces the shift in NIR flux. We establish that the ∼40-70 AU dark ring imaged in the NIR by Quanz et al. (2013) and Momose et al. (2013) and at 7 mm by Osorio et al. (2014) may be reproduced with a 30% scaled density profile throughout the region, strengthening the link to this structure being dynamically cleared by one or more planetary mass bodies.

We present the first resolved near infrared imagery of the transition disk Oph IRS 48 (WLY 2-48), which was recently observed with ALMA to have a strongly asymmetric sub-millimeter flux distribution. H-band polarized intensity images show a ∼60AU radius scattered light cavity with two pronounced arcs of emission, one from Northeast to Southeast and one smaller, fainter and more distant arc in the Northwest. K-band scattered light imagery reveals a similar morphology, but with a clear third arc along the Southwestern rim of the disk cavity. This arc meets the Northwestern arc at nearly a right angle, revealing the presence of a spiral arm or local surface brightness deficit in the disk, and explaining the East-West brightness asymmetry in the H-band data. We also present 0.8-5.4µm IRTF SpeX spectra of this object, which allow us to constrain the spectral class to A0±1 and measure a low mass accretion rate of 10 −8.5 M /yr, both consistent with previous estimates. We investigate a variety of reddening laws in order to fit the mutliwavelength SED of Oph IRS 48 and find a best fit consistent with a younger, higher luminosity star than previous estimates.

We present the first near-infrared scattered-light detection of the transitional disk around V1247 Ori, which was obtained using high-resolution polarimetric differential imaging observations with Subaru/HiCIAO. Our imaging in the H band reveals the disk morphology at separations of ∼ 0. ′′ 14-0. ′′ 86 (54-330 au) from the central star. The polarized intensity (P I) image shows a remarkable arc-like structure toward the southeast of the star, whereas the fainter northwest region does not exhibit any notable features. The shape of the arm is consistent with an arc of 0. ′′ 28 ± 0. ′′ 09 in radius (108 au from the star), although the possibility of a spiral arm with a small pitch angle cannot be excluded. V1247 Ori features an exceptionally large azimuthal contrast in scattered, polarized light; the radial peak of the southeastern arc is about three times brighter than the northwestern disk measured at the same distance from the star. Combined with the previous indication of an inhomogeneous density distribution in the gap at < ∼ 46 au, the notable asymmetry in the outer disk suggests the presence of unseen companions and/or planet-forming processes ongoing in the arc.3

We have imaged GMAurigae with the Hubble Space Telescope, detected its disk in scattered light at 1400 and 1650 Å, and compared these with observations at 3300 Å, 5550 Å, 1.1 μm, and 1.6 μm. The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300 Å shows no evidence of the 24 au radius cavity that has been previously observed in submillimeter observations. Comparison with dust grain opacity models indicates thatthe surface of the entire disk is populated with submicron grains. We have compiled aspectral energy distribution from 0.1 μm to 1mmand used it to constrain a model of the star+disk system that includes the submillimeter cavity using the Monte Carlo radiative transfer code by Barbara Whitney. The best-fit model image indicates that the cavity should be detectable in the F330W bandpass if the cavity has been cleared of both large and small dust grains, but we do not detect it. The lack of an observed cavity can be explained by the presence of submicron grains interior to the submillimeter cavity wall. We suggest one explanation for this thatcould be due to a planet of mass <9 M J interior to 24 au. A unique cylindrical structure is detected in the far-UV data from the Advanced Camera for Surveys/Solar Blind Channel. It is aligned along the system semiminor axis, but does not resemble an accretion-driven jet. The structure is limbbrightened and extends 190±35 au above the disk midplane. The inner radius of the limbbrightening is 40±10 au, just beyond the submillimeter cavity wall.