Patrick James Lowrance

Giant planet companion to 2MASSW J1207334-393254

We report new VLT/NACO imaging observations of the young, nearby brown dwarf 2MASSW J1207334-393254 and its suggested planetary mass companion (2M1207 b). Three epochs of VLT/NACO measurements obtained over nearly one year show that the planetary mass companion candidate shares the same proper motion and, with a high confidence level, is not a stationary background object. This result confirms the status of 2M1207 b as of planetary mass (5 times the mass of Jupiter) and the first image of a planetary mass companion in a different system than our own. This discovery offers new perspectives for our understanding of chemical and physical properties of planetary mass objects as well as their mechanisms of formation.

A companion to AB Pic at the planet/brown dwarf boundary

We report deep imaging observations of the young, nearby starxa0ABu2009Pic, a member of the large Tucana-Horologium association. We have detected a faint, red sourcexa0

NICMOS imaging of the HR 4796A circumstellar disk

5.5

The Circumstellar Disk of HD 141569 Imaged with NICMOS.

South of the star with JHK xa0colors compatible with that of a young substellar Lxa0dwarf. Follow-up observations at twoxa0additional epochs confirm, with a confidence level ofxa04.7 σ , that the faint red object is axa0companion toxa0ABu2009Pic rather than it being a stationary background object. A low resolution K -band spectrum indicates an early-L spectral type for the companion. Finally, evolutionary model predictions based on the JHK xa0photometry ofxa0ABu2009Picu2009b indicate a mass ofxa013 to 14xa0

A CANDIDATE SUBSTELLAR COMPANION TO HR 7329

M_{{rm Jup}}

Infrared Views of the TW Hydra Disk

if its age is ~30xa0Myr. Is ABu2009Picu2009b a massive planet or a minimum mass brown dwarf?

A Candidate Substellar Companion to CD –33°7795 (TWA 5)

We report the first near-infrared (NIR) imaging of a circumstellar annular disk around the young (~8 Myr), Vega-like star HR 4796A. NICMOS coronagraph observations at 1.1 and 1.6 μm reveal a ringlike symmetrical structure that peaks in reflected intensity 105±002 (~70 AU) from the central A0 V star. The ring geometry, with an inclination of 731±12 and a major axis position angle of 268±06, is in good agreement with recent 12.5 and 20.8 μm observations of a truncated disk. The ring is resolved with a characteristic width of less than 026 (17 AU) and appears abruptly truncated at both the inner and outer edges. The region of the disk-plane inward of ~60 AU appears to be relatively free of scattering material. The integrated flux density of the part of the disk that is visible (greater than 065 from the star) is found to be 7.6±0.5 and 7.4±1.2 mJy at 1.1 and 1.6 μm, respectively. Correcting for the unseen area of the ring yields total flux densities of 12.8±1.0 and 12.5±2.0 mJy, respectively (Vega magnitudes equal to 12.92±0.08 and 12.35±0.18). The NIR luminosity ratio is evaluated from these results and ground-based photometry of the star. At these wavelengths, L(λ)/L(λ) is equal to 1.4±0.2×10 and 2.4±0.5×10, giving reasonable agreement between the stellar flux scattered in the NIR and that which is absorbed in the visible and reradiated in the thermal infrared. The somewhat red reflectance of the disk at these wavelengths implies a mean particle size in excess of several microns, which is larger than typical interstellar grains. The confinement of material to a relatively narrow annular zone implies dynamical constraints on the disk particles by one or more as yet unseen bodies.

The Protostellar Origin of a CS Outflow in S68N

Coronagraphic imaging with the Near-Infrared Camera and Multiobject Spectrometer on the Hubble Space Telescope reveals a large, approximately 400 AU (4&arcsec;) radius, circumstellar disk around the Herbig Ae/Be star HD 141569. A reflected light image at 1.1 µm shows the disk oriented at a position angle of 356&j0;+/-5&j0; and inclined to our line of sight by 51&j0;+/-3&j0;; the intrinsic scattering function of the dust in the disk makes the side inclined toward us, the eastern side, brighter. The disk flux density peaks 185 AU (1&farcs;85) from the star and falls off to both larger and smaller radii. A region of depleted material, or a gap, in the disk is centered 250 AU from the star. The dynamical effect of one or more planets may be necessary to explain this morphology.

Infrared Imaging of GRB 970508

We present the discovery of a candidate substellar companion from a survey of nearby young stars made with the Near-Infrared Camera and Multiobject Spectrometer coronagraph on the Hubble Space Telescope. The H ≈ 12 mag object was discovered approximately 4 from the young A0 V star HR 7329. Using follow-up spectroscopy from the Space Telescope Imaging Spectrograph, we derive a spectral type between M7 V and M8 V with an effective temperature of ~2600 K. We estimate that the probability of a chance alignment with a foreground dwarf star of this nature is ~10-8, and therefore we suggest that the object (HR 7329B) is physically associated with HR 7329, with a projected separation of 200 AU. Current brown dwarf cooling models indicate a mass of less than 50 MJup for HR 7329B based on age estimates of ≤30 Myr for HR 7329A.

Using the Spitzer IRAC science archive for instrument trending

The face-on disk around TW Hya is imaged in scattered light at 1.1 and 1.6 km using the coronagraph in the Near Infrared Camera and Multi Object Spectrometer aboard the Hubble Space Telescope. Stellar light scattered from the optically thick dust disk is seen from 20 to 230 AU. The surface brightness declines as a power law of r~2.6B0.1 between 45 and 150 AU. The scattering pro—le indicates that the disk is —ared, not geometrically —at. The disk, while spatially unresolved in thermal radiation at 12 and 18 km in observations from the W. M. Keck Observatory, shows amorphous and crystalline silicate emission in its spectrum. A disk with silicate grains of a radius D1 km in size in its surface layers can explain the color of the scattered light and the shape of the mid-infrared spectrum. Much larger grains in the disk interior are necessary to —t the millimeter-wave spectral energy distribution, and hence grain growth from an original interstellar size population may have occurred.