  The centaur (2060) Chiron has exhibited outgassing behaviour and possibly
hosts a ring system. On 2011 November 29, Chiron occulted a fairly bright star
(R approximately 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 near-infrared spectra. We place a lower limit on the diameter of Chiron's
nucleus of 160.2+/-1.3 km. Sharp, narrow dips were observed between 280-360 km
from the centre (depending on event geometry). For a central chord and assumed
ring plane, the separated features are 298.5 to 302 and 308 to 310.5 km from
the nucleus, with normal optical depth approximately 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 or 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
spin-orbit resonance, which is consistent with the proposed clearing pattern
for a non-axisymmetric nucleus. Characteristics of additional, azimuthally
incomplete features are presented, which are likely to be transient, as well as
detection of an extended shell or diffuse ring from approximately 900-1500 km.
There are no significant features in the NIR light curves, nor any correlation
between optical features and NIR spectral slope.
