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Marina del Rey, CA, United States

Mainzer A.,Jet Propulsion Laboratory | Masiero J.,Jet Propulsion Laboratory | Grav T.,Johns Hopkins University | Bauer J.,Jet Propulsion Laboratory | And 11 more authors.
Astrophysical Journal | Year: 2012

We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S complex defined by previous spectrophotometrically based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vesta have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 μm is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxonomic classification is complicated by the fact that the objects with classifications were selected from the visible/near-infrared Sloan Moving Object Catalog, which is biased against fainter asteroids, including those with lower albedos. © 2012. The American Astronomical Society. All rights reserved.

Mainzer A.,Jet Propulsion Laboratory | Grav T.,Johns Hopkins University | Masiero J.,Jet Propulsion Laboratory | Bauer J.,Jet Propulsion Laboratory | And 5 more authors.
Astrophysical Journal Letters | Year: 2011

With thermal infrared observations detected by the NEOWISE project, we have measured diameters for 1742 minor planets that were also observed by the Infrared Astronomical Satellite (IRAS). We have compared the diameters and albedo derived by applying a spherical thermal model to the objects detected by NEOWISE and find that they are generally in good agreement with the IRAS values. We have shown that diameters computed from NEOWISE data are often less systematically biased than those found with IRAS. This demonstrates that the NEOWISE data set can provide accurate physical parameters for the >157,000 minor planets that were detected by NEOWISE. © 2011. The American Astronomical Society. All rights reserved.

Debes J.H.,NASA | Hoard D.W.,California Institute of Technology | Kilic M.,Smithsonian Astrophysical Observatory | Wachter S.,California Institute of Technology | And 4 more authors.
Astrophysical Journal | Year: 2011

With the launch of the Wide-Field Infrared Survey Explorer (WISE), a new era of detecting planetary debris around white dwarfs (WDs) has begun with the WISE InfraRed Excesses around Degenerates (WIRED) Survey. The WIRED survey will be sensitive to substellar objects and dusty debris around WDs out to distances exceeding 100pc, well beyond the completeness level of local WDs and covering a large fraction of known WDs detected with the SDSS DR4 WD catalog. In this paper, we report an initial result of the WIRED survey, the detection of the heavily polluted hydrogen WD (spectral type DAZ) GALEX J193156.8+011745 at 3.35 and 4.6 μm. We find that the excess is consistent with either a narrow dusty ring with an inner radius of 29 R WD, outer radius of 40 R WD, and a face-on inclination, or a disk with an inclination of 70°, an inner radius of 23 R WD, and an outer radius of 80 R WD. We also report initial optical spectroscopic monitoring of several metal lines present in the photosphere and find no variability in the line strengths or radial velocities of the lines. We rule out all but planetary mass companions to GALEX1931 out to 0.5 AU. © 2011. The American Astronomical Society. All rights reserved.

Masiero J.R.,Jet Propulsion Laboratory | Mainzer A.K.,Jet Propulsion Laboratory | Grav T.,Johns Hopkins University | Bauer J.M.,Jet Propulsion Laboratory | And 18 more authors.
Astrophysical Journal | Year: 2011

We present initial results from the Wide-field Infrared Survey Explorer (WISE), a four-band all-sky thermal infrared survey that produces data well suited for measuring the physical properties of asteroids, and the NEOWISE enhancement to the WISE mission allowing for detailed study of solar system objects. Using a NEATM thermal model fitting routine, we compute diameters for over 100,000 Main Belt asteroids from their IR thermal flux, with errors better than 10%. We then incorporate literature values of visible measurements (in the form of the H absolute magnitude) to determine albedos. Using these data we investigate the albedo and diameter distributions of the Main Belt. As observed previously, we find a change in the average albedo when comparing the inner, middle, and outer portions of the Main Belt. We also confirm that the albedo distribution of each region is strongly bimodal. We observe groupings of objects with similar albedos in regions of the Main Belt associated with dynamical breakup families. Asteroid families typically show a characteristic albedo for all members, but there are notable exceptions to this. This paper is the first look at the Main Belt asteroids in the WISE data, and only represents the preliminary, observed raw size, and albedo distributions for the populations considered. These distributions are subject to survey biases inherent to the NEOWISE data set and cannot yet be interpreted as describing the true populations; the debiased size and albedo distributions will be the subject of the next paper in this series. © 2011. The American Astronomical Society. All rights reserved.

Ressler M.E.,Jet Propulsion Laboratory | Cohen M.,Monterey Institute for Research in Astronomy | Wachter S.,California Institute of Technology | Hoard D.W.,California Institute of Technology | And 2 more authors.
Astronomical Journal | Year: 2010

We report the discovery of a pair of infrared, axisymmetric rings in the planetary nebula NGC 1514 during the course of theWISE all-sky mid-infrared survey. Similar structures are seen at visible wavelengths in objects such as the "Engraved Hourglass Nebula" (MyCn 18) and the "Southern Crab Nebula" (Hen 2-104). However, in NGC 1514 we see only a single pair of rings and they are easily observed only in the mid-infrared. These rings are roughly 0.2 pc in diameter, are separated by 0.05 pc, and are dominated by dust emission with a characteristic temperature of 160 K.We compare the morphology and color of the rings to the other nebular structures seen at visible, far-infrared, and radio wavelengths, and close with a discussion of a physical model and formation scenario for NGC 1514. © 2010. The American Astronomical Society. All rights reserved.

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