2019/11/06 by Michael S. P. Kelley, Dennis Bodewits, Quanzhi Ye +17 · 4 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Comet #Gamma-ray bursts and supernovae #Physics #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.3847/2041-8213/ab53e0
published in The Astrophysical Journal Letters 886(1), L16 (IOP Publishing) · Accepted for publication in the Astrophysical Journal Letters. 11 pages, 4 figures
arxiv created 2019/11/06 · openalex publication_date 2019/11/18 · arxiv updated 2020/01/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Comets are primitive objects that formed in the protoplanetary disk, and have been largely preserved over the history of the solar system. However, they are not pristine, and surfaces of cometary nuclei do evolve. In order to understand the extent of their primitive nature, we must define the mechanisms that affect their surfaces and comae. We examine the lightcurve of comet 240P/NEAT over three consecutive orbits, and investigate three events of significant brightening (Δ m ∼ −2 mag). Unlike typical cometary outbursts, each of the three events are long-lived, with enhanced activity for at least 3–6 months. The third event, observed by the Zwicky Transient Facility, occurred in at least two stages. The anomalous behavior appears to have started after the comet was perturbed by Jupiter in 2007, reducing its perihelion distance from 2.53 to 2.12 au. We suggest that the brightening events are temporary transitions to a higher baseline activity level, brought on by the increased insolation, which has warmed previously insulated sub-surface layers. The new activity is isolated to one or two locations on the nucleus, indicating that the surface or immediate sub-surface is heterogeneous. Further study of this phenomenon may provide insight into cometary outbursts, the structure of the near-surface nucleus, and cometary nucleus mantling.