# # Program information file # PROGRAM_ID 2021A029 PROGRAM_TITLE Stellar occultations by Ixion, Quaoar, and 95626 PROGRAM_INV1 Amanda Sickafoose PROGRAM_INV2 Carlos Zuluaga PROGRAM_INV3 Amanda Bosh PROGRAM_INV4 Stephen Levine PROGRAM_INV5 Michael Person PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG The capabilities of MORIS+SpeX, combined with Hawaii's unique geographic location, have proven successful for observing stellar occultations by Trans-Neptunian Objects [TNOs]. High-quality, high-time-resolution, multiple-wavelength datasets have been obtained for occultations by Pluto, Charon, Chiron, Vanth [a satellite of Orcus], and Chariklo. In 2021A, we propose for 24 hours to observe six predicted stellar occultations of bright stars by the TNOs Ixion, Quaoar, and 95626 [2002 GZ32]. Successful observations will [i] constrain the object/nucleus size and [ii] detect and characterize any tenuous atmospheres or surrounding rings/material for all the objects. The UT mid-times for the predicted events are on 12 May [Ixion], 13 May [Ixion], 19 May [Ixion], 02 June [Quaoar], 09 June [95626], and 20 June [Ixion]. We request 4 hours for each of the events. We observe at high cadence for +/-20 min centered on each predicted midtime. When possible, long-exposure, calibration frames are taken before and after, when the star and object are well separated. MORIS will be run with no filter at the fastest cadence that allows for a light-curve signal-to-noise of at least a few tens: for these targets, the resulting integration times are between 0.01 and 0.2 sec. SpeX will be employed to obtain simultaneous K-band images for the events depending on conditions. Visible data are used to constrain object sizes and atmospheres, as well as the extent and structure of surrounding material. Multi-color data provide an additional level of characterization, through providing insight into [i] particle sizes in atmospheric haze or surrounding material and [ii] nucleus shapes, through central-flash modeling. PROGRAM_ABSTRACT_END