WISE/NEOWISE Observations of the Hilda Population: Preliminary Results

January 2012 • 2012ApJ...744..197G

Authors • Grav, T. • Mainzer, A. K. • Bauer, J. • Masiero, J. • Spahr, T. • McMillan, R. S. • Walker, R. • Cutri, R. • Wright, E. • Eisenhardt, P. R. • Blauvelt, E. • DeBaun, E. • Elsbury, D. • Gautier, T. • Gomillion, S. • Hand, E. • Wilkins, A.

Abstract • We present the preliminary analysis of 1023 known asteroids in the Hilda region of the solar system observed by the NEOWISE component of the Wide-field Infrared Survey Explorer (WISE). The sizes of the Hildas observed range from ~3 to 200 km. We find no size-albedo dependency as reported by other projects. The albedos of our sample are low, with a weighted mean value of p_V = 0.055 ± 0.018, for all sizes sampled by the NEOWISE survey. We observed a significant fraction of the objects in the two known collisional families in the Hilda population. It is found that the Hilda collisional family is brighter, with a weighted mean albedo of p_V = 0.061 ± 0.011, than the general population and dominated by D-type asteroids, while the Schubart collisional family is darker, with a weighted mean albedo of p_V = 0.039 ± 0.013. Using the reflected sunlight in the two shortest WISE bandpasses, we are able to derive a method for taxonomic classification of ~10% of the Hildas detected in the NEOWISE survey. For the Hildas with diameter larger than 30 km, there are 67⁺⁷ _{- 15}% D-type asteroids and 26⁺¹⁷ _{- 5}% C-/P-type asteroids (with the majority of these being P-types).

Links

• PDF https://iopscience.iop.org/article/10.1088/0004-637X/744/2/197/pdf
• PREPRINT http://arxiv.org/abs/1110.0283
• DATA http://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/744/197
• ELECTR https://iopscience.iop.org/article/10.1088/0004-637X/744/2/197
• SPIRES http://inspirehep.net/search?p=find+eprint+arXiv:1110.0283