TY - JOUR
T1 - Characterization of material around the centaur (2060) Chiron from a visible and near-infrared stellar occultation in 2011
AU - Sickafoose, A. A.
AU - Bosh, A. S.
AU - Emery, J. P.
AU - Person, M. J.
AU - Zuluaga, C. A.
AU - Womack, M.
AU - Ruprecht, J. D.
AU - Bianco, F. B.
AU - Zangari, A. M.
N1 - Funding Information:
This work was partially supported the South African National Research Foundation. ASB and AAS were visiting astronomers at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. The work includes observations obtained with LCOGT network, which is owned and operated by Las Cumbres Observatory network and the SARA Observatory, which is owned and operated by the Southeastern Association for Research in Astronomy (saraobservatory.org). MW acknowledges support from National Sciance Foundation grant AST-1615917. Thanks to S.J. Bus who was part of the original data acquisition and analysis team. AMZ and JDR are currently Massachusetts Instiutute of Technology Lincoln Laboratory employees. No Laboratory funding or resources were used to produce the result/findings reported in this publication.
Publisher Copyright:
© 2020 Oxford University Press. All rights reserved.
PY - 2020
Y1 - 2020
N2 - 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.
AB - 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.
KW - Comets: Individual: Chiron
KW - Methods: Observational
KW - Minor planets, asteroids: Individual: Chiron
KW - Occultations
KW - Planets and satellites: Rings
KW - Techniques: Photometric
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U2 - 10.1093/MNRAS/STZ3079
DO - 10.1093/MNRAS/STZ3079
M3 - Article
AN - SCOPUS:85088874354
SN - 0035-8711
VL - 491
SP - 3643
EP - 3654
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -