The Discovery and Evolution of a Possible New Epoch of Cometary Activity by the Centaur (2060) Chiron
: Dobson, M.M.; Schwamb, M.E.; Fitzsimmons, A; Schambeau, C.; Beck, A.; Denneau, L.; Erasmus, N; Heinze, A.N.; Shingles L.J.; Siverd R.J.; Smit,h K.W.; Tonry, J.L.; Weiland, H.; Young, D.R.; Kelley, M.S.P.; Lister, T.; Bernardinelli, P.H.; Ferrais M.; Jehin, E.; Fedorets, G.; Benecchi, S.D.; Verbiscer, A.J.; Murtagh, J.; Duffard, R.; Gomez, E.; Chatelain, J.; Greenstreet, S.
Publisher: Institute of Physics Publishing
: 2024
: The Planetary Science Journal
: Planetary Science Journal
: 165
: 5
: 7
: 2632-3338
DOI: https://doi.org/10.3847/PSJ/ad543c
: https://doi.org/10.3847/PSJ/ad543c
: https://research.utu.fi/converis/portal/detail/Publication/457432576
Centaurs are small solar system objects on chaotic orbits in the giant planet region, forming an evolutionary continuum with the Kuiper Belt objects and Jupiter-family comets. Some Centaurs are known to exhibit cometary activity, though unlike comets, this activity tends not to correlate with heliocentric distance, and the mechanism behind it is currently poorly understood. We utilize serendipitous observations from the Asteroid Terrestrial-impact Last Alert System, Zwicky Transient Facility, Panoramic Survey Telescope and Rapid Response System, Dark Energy Survey, and Gaia in addition to targeted follow-up observations from the Las Cumbres Observatory, TRAnsiting Planets and PlanetesImals Small Telescope South (TRAPPIST-South), and Gemini North telescope to analyze an unexpected brightening exhibited by the known active Centaur (2060) Chiron in 2021. This is highly indicative of a cometary outburst. As of 2023 February, Chiron had still not returned to its prebrightening magnitude. We find Chiron's rotational lightcurve, phase curve effects, and possible high-albedo surface features to be unlikely causes of this observed brightening. We consider the most likely cause to be an epoch of either new or increased cometary activity, though we cannot rule out a possible contribution from Chiron's reported ring system, such as a collision of as-yet-unseen satellites shepherding the rings. We find no evidence for a coma in our Gemini or TRAPPIST-South observations, though this does not preclude the possibility that Chiron is exhibiting a coma that is too faint for observation or constrained to the immediate vicinity of the nucleus.
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University of Hawai'i, UH; Department for the Economy, DfE; Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University; University of Wisconsin-Milwaukee, UWM; Science and Technology Facilities Council, STFC; University of Edinburgh, ED; Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ; Johns Hopkins University, JHU; Ohio State University, OSU; Eotvos Lorand University; University of Chicago, U of C; Royal Astronomical Society, RAS; Higher Education Funding Council for England, HEFCE; Los Alamos National Laboratory, LANL; Financiadora de Estudos e Projetos, FINEP; Space Telescope Science Institute, STScI; Max-Planck-Gesellschaft, MPG; Ministry of Education and Science of Ukraine, MESU; Harvard-Smithsonian Center for Astrophysics; ELTE; Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq; DIRAC Institute; Deutsche Forschungsgemeinschaft, DFG; National Central University of Taiwan; U.S. Department of Energy, USDOE; Weizmann Institute of Science, WIS; Durham University; University of Maryland, UMD; Science and Technology Facilities Council of the United Kingdom; Ministério da Ciência, Tecnologia e Inovação, MCTI; Queen's University Belfast, QUB; DfE) Northern Ireland; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Max Planck Institute for Astronomy; Pan-STARRS Project Office; University of Washington, UW; European Research Council, ERC; Washington Research Foundation, WRF; Max Planck Institute for Extraterrestrial Physics; Charles and Lisa Simonyi Fund for Arts and Sciences; Collaborating Institutions in the Dark Energy Survey; Gordon and Betty Moore Foundation, GBMF; European Union's Horizon 2020 research and innovation program, 885281; National Aeronautics and Space Administration, NASA, NNX08AR22G; NASA, 80NSSC18K1575, NN12AR55G, J1944/80NSSC19K0112, HST GO-15889, 80NSSC18K0284, 80NSSC20K0673; Belgian Fonds (National) de la Recherche Scientifique, PDR T.0120.21; H2020 Marie Skłodowska-Curie Actions, MSCA, 101032479; National Science Foundation, NSF, AST-1238877, AST-1440341; LSST, ST/N002512/1, ST/S006206/1; STFC, ST/V000691/1, ST/X001253/1, ST/V506990/1, ST/T000198/1, ST/S006109/1
