Characterization of material around the centaur (2060) Chiron from a visible and near-infrared stellar occultation in 2011

A. A. Sickafoose, A. S. Bosh, J. P. Emery, M. J. Person, C. A. Zuluaga, M. Womack, J. D. Ruprecht, F. B. Bianco, A. M. Zangari

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The centaur (2060) Chiron exhibits outgassing behaviour and possibly hosts a ring system. On 2011 November 29, Chiron occulted a fairly bright star (R ∼ 15 mag) as observed from the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and the 2-m Faulkes Telescope North (FTN) at Haleakala. Data were taken as visible wavelength images and simultaneous, low-resolution, near-infrared (NIR) spectra. Here, we present a detailed examination of the light-curve features in the optical data and an analysis of the NIR spectra. We place a lower limit on the spherical diameter of Chiron's nucleus of 160.2±1.3 km. Sharp, narrow dips were observed between 280 and 360 km from the centre (depending on event geometry). For a central chord and assumed ring plane, the separated features are 298.5-302 and 308-310.5 km from the nucleus, with normal optical depth ∼0.5-0.9, and a gap of 9.1 ± 1.3 km. These features are similar in equivalent depth to Chariklo's inner ring. The absence of absorbing/scattering material near the nucleus suggests that these sharp dips are more likely to be planar rings than a shell of material. The region of relatively increased transmission is within the 1:2 spinorbit resonance, consistent with the proposed clearing pattern for a non-axisymmetric nucleus. Characteristics of possible azimuthally incomplete features are presented, which could be transient, as well as a possible shell from ∼900-1500 km: Future observations are needed for confirmation. There are no significant features in the NIR light curves, nor any correlation between optical features and NIR spectral slope.

Original languageEnglish (US)
Pages (from-to)3643-3654
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume491
Issue number3
DOIs
StatePublished - 2020

Keywords

  • Comets: Individual: Chiron
  • Methods: Observational
  • Minor planets, asteroids: Individual: Chiron
  • Occultations
  • Planets and satellites: Rings
  • Techniques: Photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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