2008/03/20 by Gy. M. Szabó, Gy. M. Szabo, L. L. Kiss +2 · 4 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Planetary Science and Exploration #astro-ph
paper · pdf · doi:10.1086/588095
v2: typos corrected. 13 pages, 5 figures, 1 table, ApJ Letters, in press
arxiv created 2008/03/20 · openalex publication_date 2008/03/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
Eleven years after its perihelion, comet C/1995 O1 (Hale-Bopp) is still active. Between 2007 October 20 and 22, we detected a diffuse coma of 180 × 10 3 km in diameter with a slight elongation toward the north-south direction. The integrated brightness was 20.04 mag in R C , implying Af ρ = 300 m and albedo × dust surface a R C = 4300 km 2 . The coma was relatively red at V − R = 0.66 mag, which is consistent with that of the dust in other comets. The observed properties and the overall fading in brightness between 10 and 26 AU follow the predicted behavior of CO-driven activity. This is the most distant cometary activity ever observed.