The intermittent turbulent transport in the scrape-off-layer (SOL) of Alcator C-Mod [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nucl. Fusion 41, 1391 (2001)] is studied experimentally by imaging with a very high density of spatial measurements. The two-dimensional structure and dynamics of emission from a localized gas puff are observed, and intermittent features (also sometimes called "filaments" or "blobs") are typically seen. The characteristics of the spatial structure of the turbulence and their relationship to the time-averaged SOL profiles are discussed and compared with those measured on the National Spherical Torus Experiment [M. Ono, S. M. Kaye, Y.-K. M. Pong et al., Nucl. Fusion 40, 557 (2000)]. The experimental observations are compared also with three-dimensional nonlinear numerical simulations of edge turbulence. Radial profiles of the poloidal wave number spectra and the poloidal scale length from the simulations are in reasonable agreement with those obtained from the experimental images, once the response of the optical system is accounted for. The resistive ballooning mode is the dominant linear instability in the simulations. The ballooning character of the turbulence is also consistent with fluctuation measurements made at the inboard and outboard midplane, where normalized fluctuation levels are found to be about 10 times smaller on the inboard side. For discharges near the density limit, turbulent structures are seen on closed flux surfaces

Young giant exoplanets are a unique laboratory for understanding cool, low-gravity atmospheres. A quintessential example is the massive extrasolar planet β Pic b, which is 9 AU from and embedded in the debris disk of the young nearby A6V star β Pictoris. We observed the system with first light of the Magellan Adaptive Optics (MagAO) system. In Paper I (Males et al. 2014) we presented the first CCD detection of this planet with MagAO+VisAO. Here we present four MagAO+Clio images of β Pic b at 3.1 µm, 3.3 µm, L ′ , and M ′ , including the first observation in the fundamental CH 4 band. To remove systematic errors from the spectral energy distribution (SED), we re-calibrate the literature photometry and combine it with our own data, for a total of 22 independent measurements at 16 passbands from 0.99-4.8 µm. Atmosphere models demonstrate the planet is cloudy but are degenerate in effective temperature and radius. The measured SED now covers >80% of the planet's energy, so we approach the bolometric luminosity empirically. We calculate the luminosity by extending the measured SED with a blackbody and integrating to find log(L bol /L ⊙ ) = −3.78 ± 0.03. From our bolometric luminosity and an age of 23±3 Myr, hot-start evolutionary tracks give a mass of 12.7±0.3 M Jup , radius of 1.45±0.02 R Jup , and T eff of 1708±23 K (model-dependent errors not included). Our empirically-determined luminosity is in agreement with values from atmospheric models (typically −3.8 dex), but brighter than values from the field-dwarf bolometric correction (typically −3.9 dex), illustrating the limitations in comparing young exoplanets to old brown dwarfs.

We utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high spatial resolution observations in "visible light" with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0.5 − 0.7 ′′ ) we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60s) r' (0.63µm) images are slightly coarser at FWHM=23-29 mas (Strehl ∼ 28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young (∼ 1 Myr) Orion Trapezium θ 1 Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary θ 1 Ori C 1 C 2 was easily resolved in non-interferometric images for the first time. Relative positions of the bright trapezium binary stars were measured with ∼ 0.6 − 5 mas accuracy. We now 01 This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile. are sensitive to relative proper motions of just ∼ 0.2 mas/yr (∼ 0.4 km/s at 414 pc) -this is a ∼ 2 − 10× improvement in orbital velocity accuracy compared to previous efforts. For the first time, we see clear motion of the barycenter of θ 1 Ori B 2 B 3 about θ 1 Ori B 1 . All five members of the θ 1 Ori B system appear likely a gravitationally bound "mini-cluster", but we find that not all the orbits can be both circular and co-planar. The lowest mass member of the θ 1 Ori B system (B 4 ; mass ∼ 0.2M ⊙ ) has a very clearly detected motion (at 4.1 ± 1.3 km/s; cor-relation=99.9%) w.r.t B 1 . Previous work has suggested that B 4 and B 3 are on long-term unstable orbits and will be ejected from this "mini-cluster". However, our new "baseline" model of the θ 1 Ori B system suggests a more hierarchical system than previously thought, and so the ejection of B 4 may not occur for many orbits, and B 3 may be stable against ejection long-term. This "ejection" process of the lowest mass member of a "mini-cluster" could play a major role in the formation of low mass stars and brown dwarfs.

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