1995/09/19 by Anita L. Cochran, Harold F. Levison, S. Alan Stern +1 · 5 citations
Physics and Astronomy · #Astro and Planetary Science #History and Developments in Astronomy #Planetary Science and Exploration #astro-ph
paper · pdf · doi:10.1086/176581
11 pages of text plus three figures attached with epsf macros, uses AASTeX macros (aaspp), to appear in 10 December 1995 Astrophysical Journal
arxiv created 1995/09/19 · openalex publication_date 1995/12/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We report the statistical detection (at the >99% confidence level) of a population of 28th magnitude objects exhibiting proper motions of ≈1" hr<SUP>-1</SUP> at quadrature in deep Hubble Space Telescope (HST)/WFPC2 images. The drift directions imply a preponderance of objects on prograde orbits concentrated near the ecliptic plane. We interpret this as the detection of objects which reside in the Kuiper belt near or beyond the orbit of Neptune, comparable in size to comet 1P/Halley (radii ∼10 km for an albedo of 4%). Our observations imply a population of ∼2.5 × 10<SUP>4</SUP> objects deg<SUP>-2</SUP> with V <28.6. This must be viewed as a lower limit until our search of parameter space is complete. Our observations imply that there are >2 × 10<SUP>8</SUP> objects of this size in the Kuiper belt with inclinations <12° and within ∼40 AU of the Sun.