Direct Detection of the Brown Dwarf GJ 802B with Adaptive Optics Masking Interferometry

We have used the Palomar 200" Adaptive Optics (AO) system to directly detect the astrometric brown dwarf GJ 802B reported by Pravdo et al. 2005. This observation is achieved with a novel combination of aperture masking interferometry and AO. The dynamical masses are 0.175$\pm$0.021 M$_\odot$ and 0.064$\pm$0.032 M$_\odot$ for the primary and secondary respectively. The inferred absolute H band magnitude of GJ 802B is M$_H$=12.8 resulting in a model-dependent T$_\mathrm{eff}$ of 1850 $\pm$ 50K and mass range of 0.057--0.074 M$_\odot$.Comment: 4 Pages, 5 figures, emulateapj format, submitted to ApJ

Precision Masses of the low-mass binary system GJ 623

We have used Aperture Masking Interferometry and Adaptive Optics (AO) at the Palomar 200'' to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 years combined with a decade of radial velocity measurements constrain all orbital parameters of the GJ 623 binary system accurately enough to critically challenge the models. The dynamical masses measured are m_{1}=0.371\pm0.015 M_{\sun} (4%) and m_{2}=0.115\pm0.0023 M_{\sun} (2%) for the primary and the secondary respectively. Models are not consistent with color and mass, requiring very low metallicities.Comment: 7 pages, 5 figures. Accepted for Ap

Masses of Astrometrically-Discovered and Imaged Binaries: G 78-28AB and GJ 231.1BC

The Stellar Planet Survey (STEPS) is an ongoing astrometric search for giant planets and brown dwarfs around a sample of ~30 M-dwarfs. We have discovered several low-mass companions by measuring the motion of our target stars relative to their reference frames. The highest mass discovery thus far is G 78-28B, a companion to the M-dwarf G 78-28A. The orbital period is 4.18 +/- 0.03 y, the system mass is 0.565 +/- 0.055 Msolar, and the semi-major axis is 2.19 +/- 0.10 AU. Imaging observations with the Keck laser guide star adaptive optics (LGSAO) and the Palomar AO instruments resolved the system and also yielded JHK-band delta magnitudes. We use the orbital solution, light ratios, and mass-luminosity relationships to derive component masses of MA = 0.370 +/- 0.034 Msolar and MB = 0.195 +/- 0.021 Msolar. G 78-28B is of type M4 V based upon its colors and mass. We also discovered GJ 231.1C, a companion to GJ 231.1B, with STEPS and imaged the companion with LGSAO and Palomar AO, but the orbital period is longer than our observing baseline; thus the system parameters are less constrained. In GJ 231.1BC the masses are MB = 0.25 +/- 0.06 Msolar and MC =0.12 +/- 0.02 Msolar. The inferred spectral type of GJ 231.1C is M5 V. We demonstrate the results of the current state of mass estimation techniques with our data.Comment: 25 pages, 8 figures, accepted for Ap

The Palomar kernel-phase experiment: testing kernel phase interferometry for ground-based astronomical observations

At present, the principal limitation on the resolution and contrast of astronomical imaging instruments comes from aberrations in the optical path, which may be imposed by the Earth's turbulent atmosphere or by variations in the alignment and shape of the telescope optics. These errors can be corrected physically,with active and adaptive optics, and in post-processing of the resulting image.Arecently developed adaptive optics post-processing technique, called kernelphase interferometry, uses linear combinations of phases that are self-calibrating with respect to small errors, with the goal of constructing observables that are robust against the residual optical aberrations in otherwise well-corrected imaging systems. Here, we present a direct comparison between kernel phase and the more established competing techniques, aperture masking interferometry, point spread function (PSF) fitting and bispectral analysis.We resolve the α Ophiuchi binary system near periastron, using the Palomar 200-Inch Telescope. This is the first case in which kernel phase has been used with a full aperture to resolve a system close to the diffraction limit with ground-based extreme adaptive optics observations. Excellent agreement in astrometric quantities is found between kernel phase and masking, and kernel phase significantly outperforms PSF fitting and bispectral analysis, demonstrating its viability as an alternative to conventional non-redundant masking under appropriate conditions

The effect of lysine level or methionine/copper/manganese on osteochondrosis lesions and cartilage properties in pigs

A total of 120 gilts (PIC 327 × 1050; 89.2 lb initial BW) were used in a 3 × 2 factorial, 84-d study to determine the effect of lysine (Lys) fed either below the calculated requirement (0.8% true ileal digestible (TID) Lys Phase I and 0.6% TID Lys Phase II), at requirement (1.0% TID Lys Phase I and 0.8% TID Lys Phase II), or above the requirement (1.3% TID Lys Phase I and 1.1% TID Lys Phase II) with standard concentrations or with high added methionine (Met, 1 %), copper sulfate (Cu, 250 ppm), and manganese sulfate (Mn, 220 ppm) on the occurrence and severity of osteochondrosis (OC) lesions, growth performance, soundness, carcass traits, and several cartilage criteria. Upon completion of the feeding period, pigs were harvested and the distal aspect of the left humerus and femur were evaluated by gross examination for OC lesions. The external surface was evaluated for abnormalities and received a severity score. For the external femur evaluation, increasing dietary Lys concentration tended (linear, P\u3c0.08) to increase the number of abnormalities and there was a numerical trend for an increased severity score (P\u3c0.13) with increasing dietary Lys. The addition of high Met/Cu/Mn to the diet reduced the number of abnormalities (P\u3c0.02) and severity score (P\u3c0.01) at the external femur compared to pigs fed diets with standard concentrations of Met/Cu/Mn. At the external humerus, increasing dietary Lys increased both the number of abnormalities (linear, P\u3c0.01) and severity score (linear, P\u3c0.01). The addition of high Met/Cu/Mn to the diet reduced the number of abnormalities (P\u3c0.03) and severity score (P\u3c0.03) for the external humerus. Increasing dietary Lys concentration or high-added Met/Cu/Mn had no effect (P\u3e0.14) on the number of faces with lesions at the femoral growth plate or the severity score (P\u3e0.19). The number of faces with lesions and severity score at the humerus articular cartilage was unaffected by increasing dietary Lys concentration (P\u3e0.16) or the addition of high Met/Cu/Mn to the diet (P\u3e0.37). The total faces with lesions were not impacted by increasing dietary Lys concentration (P\u3e0.78) or additional high Met/Cu/Mn (P\u3e0.86). The total abnormalities (external and number of faces) tended to increase with increasing dietary Lys (linear, P\u3c0.12). The addition of high Met/Cu/Mn did not affect the total number of abnormalities (P\u3e0.16). The total severity score for both external and OC evaluation increased with increasing dietary Lys concentration (linear, P\u3c0.01). The addition of high Met/Cu/Mn decreased the total severity score (P\u3c0.02) compared to pigs fed diets with standard concentrations of Met/Cu/Mn. Finally, increasing dietary Lys concentration increased the sum (linear, P\u3c0.05) of abnormalities and total severity score. The addition of high Met/Cu/Mn tended (P\u3c0.09) to reduce the overall severity score compared to pigs fed diets with standard concentrations of Met/Cu/Mn. In conclusion, feeding growing gilts dietary Lys to maximize growth performance may increase the severity of OC lesions, while a diet with additional Met/Cu/Mn may aid in the reduction of OC severity scores.; Swine Day, 2007, Kansas State University, Manhattan, KS, 200

Planetary system and star formation science with non-redundant masking on JWST

Non-redundant masking (NRM) is a high contrast high resolution technique that is relevant for future space missions dedicated to either general astrophysics or extrasolar planetary astronomy. NRM mitigates not only atmospheric but instrument-induced speckle noise as well. The recently added mask in the Fine Guidance Sensor Tunable Filter Imager (FGS-TFI) on the James Webb Space Telescope (JWST) will open up a search space between 50 and 400 mas at wavelengths longer than 3.8μm. Contrast of 104 will be achievable in a 10 ks exposure of an M = 7 star, with routine observing, target acquisition, and data calibration methods. NRM places protoplanets in Taurus as well as Jovians younger than 300Myr and more massive than 2MJ orbiting solar type stars within JWST's reach. Stars as bright as M = 3 will also be observable, thus meshing well with next-generation ground-based extreme adaptive optics coronagraphs. This parameter space is inaccessible to both JWST coronagraphs and future 30-m class ground-based telescopes, especially in the mid-IR. We show that NRM used on future space telescopes can deliver unsurpassed image contrast in key niches, while reducing mission risk associated with active primary mirrors

Solid-pseudopapillary tumour of the pancreas as a rare cause of gastric outlet obstruction: a case report

The presence of a large bulky pancreatic tumour in a young female should raise suspicions of the diagnosis of solid-pseduopapillary tumour of the pancreas

Planetary system and star formation science with non-redundant masking on JWST

Non-redundant masking (NRM) is a high contrast high resolution technique that is relevant for future space missions dedicated to either general astrophysics or extrasolar planetary astronomy. On the ground NRM has opened a rich target space between 0.5 to 4 resolution elements from bright stars. It enabled moderate contrast very high angular resolution observations that have provided dynamical masses for targets beyond the resolution of the Hubble Space Telescope. Such observations challenge the best models of ultra-cool dwarf stars' atmospheres and interiors. The technique succeeds because it sidesteps the effects of speckle noise that plagues direct imaging at moderate Strehl ratios. On a space telescope NRM mitigates instrument-induced speckle noise, thus enabling high contrast even when images are barely diffraction-limited. The non-redundant mask in the Fine Guidance Sensor Tunable Filter Imager (FGS-TFI) on the James Webb Space Telescope (JWST) will open up a search space between 50 and 400 mas at wavelengths longer than 3.8μm. We present simulations that estimate achievable contrast on JWST, and report preliminary results of a testbed experiment using a mask with the same geometry as JWST's. We expect contrast of the order of 104 will be achievable in a 10 ks exposure of an M = 7 star, with observing, target acquisition, and data calibration methods common to the three other imaging instruments on board JWST. As an example of the potential science possible with NRM, we show that if a planet were responsible for clearing the inner 5 AU of the disk around HR8799, it would likely be detectable using JWST FGS-TFI's NRM at 4.6 microns. Stars as bright as M = 3 will also be observable with JWST's NRM, meshing well with next-generation ground-based extreme adaptive optics coronagraphs. JWST NRM's parameter space is inaccessible to both JWST coronagraphs and future 30-m class ground-based telescopes, especially in the mid-IR

A Close Companion Search Around L Dwarfs Using Aperture Masking Interferometry and Palomar Laser Guide Star Adaptive Optics

We present a close companion search around 16 known early L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics (LGS AO). The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targets of our survey. This survey achieved median contrast limits of ΔK ~ 2.3 for separations between 1.2λ/D-4λ/D and ΔK ~ 1.4 at 2/3λ/D. We present four candidate binaries detected with moderate-to-high confidence (90%-98%). Two have projected physical separations less than 1.5 AU. This may indicate that tight-separation binaries contribute more significantly to the binary fraction than currently assumed, consistent with spectroscopic and photometric overluminosity studies. Ten targets of this survey have previously been observed with the Hubble Space Telescope as part of companion searches. We use the increased resolution of aperture masking to search for close or dim companions that would be obscured by full aperture imaging, finding two candidate binaries. This survey is the first application of aperture masking with LGS AO at Palomar. Several new techniques for the analysis of aperture masking data in the low signal-to-noise regime are explored

Visual orbit of GJ 164 AB

We report seven successful observations of the astrometric binary GJ 164 AB system with aperture masking interferometry. The companion, with a near infrared contrast of 5:1 was detected beyond the formal diffraction limit. Combined with astrometric observations from the literature, these observations fix the parallax of the system, and allow a model-independent mass determination of both components. We find the mass of GJ 164B to be 0.086 \pm 0.007 M_{\sun}. An infrared spectroscopic study of a sample of M-Dwarfs outlines a method for calibrating metallicity of M-Dwarfs. Results from the newly commissionned TripleSpec spectrograph reveal that the GJ 164 system is at least of Solar metallicity. Models are not consistent with color and mass, requiring a very young age to accommodate a secondary too luminous, a scenario ruled out by the kinematics.Comment: 9 pages, 8 figures. Submitted to Ap