English

The changing material around (2060) Chiron from an occultation on 2022 December 15

Earth and Planetary Astrophysics 2023-08-23 v1

Abstract

We could accurately predict the shadow path and successfully observe an occultation of a bright star by Chiron on 2022 December 15. The Kottamia Astronomical Observatory in Egypt did not detect the occultation by the solid body, but we detected 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 \sim25%\% 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 \sim580 km disk with concentrations at radii of 325 \pm 16 km and 423 \pm 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\lambda = 151 ±^\circ~\pm 8^\circ and β\beta = 18 ±^\circ~\pm 11^\circ, in agreement with previous results. We also show our long-term photometry 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 if it emanated from it.

Keywords

Cite

@article{arxiv.2308.03458,
  title  = {The changing material around (2060) Chiron from an occultation on 2022 December 15},
  author = {J. L. Ortiz and C. L. Pereira and B. Sicardy and F. Braga-Ribas and A. Takey and A. M. Fouad and A. A. Shaker and S. Kaspi and N. Brosch and M. Kretlow and R. Leiva and J. Desmars and B. E. Morgado and N. Morales and M. Vara-Lubiano and P. Santos-Sanz and E. Fernández-Valenzuela and D. Souami and R. Duffard and F. L. Rommel and Y. Kilic and O. Erece and D. Koseoglu and E. Ege and R. Morales and A. Alvarez-Candal and J. L. Rizos and J. M. Gómez-Limón and M. Assafin and R. Vieira-Martins and A. R. Gomes-Júnior and J. I. B. Camargo and J. Lecacheux},
  journal= {arXiv preprint arXiv:2308.03458},
  year   = {2023}
}

Comments

6 pages, 4, figures