Stellar Occultations by Trans-Neptunian Objects and Centaurs

Principal Investigator

Juergen Wolf

Proposal ID

04_0145

Category

SOLAR SYSTEM

Keywords

• KUIPER BELT OBJECTS
• COMETS
• ASTEROIDS
• IMAGING

Abstract

Our solar system beyond Neptune's orbit is populated with numerous small objects, referred to as Trans-Neptunian Objects (TNOs). About 1400 TNOs are known today ranging in size from the most prominent one, Pluto (2370 km diameter), down to a few tens of kilometers. Most diameters have been determined by radiometric methods in the IR/FIR (SPITZER, HERSCHEL) with uncertainties in the 20% range. Only for Pluto and about 12 other objects have the projected diameters been measured more accurately by stellar occultations. A group of objects lingering between the orbits of Jupiter and Neptune, the Centaurs, are believed to have originated from TNOs. Two of them, Chariklo and Chiron, have recently drawn attention, as stellar occultations have revealed rings around them. Our proposed occultation observations with SOFIA shall add to the sparse knowledge on TNOs and Centaurs by determining more projected diameters and albedos. They have the potential of detecting moons, rings and atmospheres. We will use SOFIA's demonstrated capability of measuring occultations (Pluto 2011 & 2015) with its Focal Plane Imager (FPI) to observe up to five events on flight legs of approximately 30 min each. As most of these events cannot be predicted accurately enough more than a few months or weeks ahead of time, we propose these as targets of opportunity.