Changing material around (2060) Chiron revealed by an occultation on December 15, 2022

J. L. Ortiz*, C. L. Pereira, B. Sicardy, F. Braga-Ribas, A. Takey, A. M. Fouad, A. A. Shaker, S. Kaspi, N. Brosch, M. Kretlow, R. Leiva, J. Desmars, B. E. Morgado, N. Morales, M. Vara-Lubiano, P. Santos-Sanz, E. Fernández-Valenzuela, D. Souami, R. Duffard, F. L. RommelY. Kilic, O. Erece, D. Koseoglu, E. Ege, R. Morales, A. Alvarez-Candal, J. L. Rizos, J. M. Gómez-Limón, M. Assafin, R. Vieira-Martins, A. R. Gomes-Júnior, J. I.B. Camargo, J. Lecacheux

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We were able to accurately predict the shadow path and successfully observe an occultation of a bright star by Chiron on December 15, 2022. The Kottamia Astronomical Observatory in Egypt did not detect the occultation by the solid body, but we found three extinction features in the light curve that had symmetrical counterparts with respect to the central time of the occultation. One of the features is broad and shallow, whereas the other two features are sharper, with a maximum extinction of ∼25% at the achieved spatial resolution of 19 km per data point. From the Wise Observatory in Israel, we detected the occultation caused by the main body and several extinction features surrounding the body. When all the secondary features are plotted in the sky plane, we find that they can be caused by a broad ∼580 km disk with concentrations at radii of 325 ± 16 km and 423 ± 11 km surrounding Chiron. At least one of these structures appears to be outside the Roche limit. The ecliptic coordinates of the pole of the disk are λ = 151° ±8 and β = 18° ±11, in agreement with previous results. We also reveal our long-term photometry results, indicating that Chiron had suffered a brightness outburst of at least 0.6 mag between March and September 2021 and that Chiron was still somewhat brighter at the occultation date than at its nominal pre-outburst phase. The outermost extinction features might be consistent with a bound or temporarily bound structure associated with the brightness increase. However, the nature of the brightness outburst is unclear, and it is also unclear whether the dust or ice released in the outburst could be feeding a putative ring structure or whether it is emanating from it.

Original languageEnglish
Article numberL12
JournalAstronomy and Astrophysics
Volume676
DOIs
StatePublished - 1 Aug 2023

Funding

FundersFunder number
Proyecto de Excelencia de la Junta de AndalucíaPY20-01309, CEX2021-001131-S
Direktion für Entwicklung und ZusammenarbeitE26/204.141/2022
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
National Research Institute of Astronomy and Geophysics
Science and Technology Development Fund45779
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Ministerio de Ciencia e Innovación
Agencia Estatal de Investigación

    Keywords

    • Asteroids: individual: Chiron
    • Comets: general
    • Kuiper belt: general
    • Minor planets
    • Occultations

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