Astrometry Request for TNO Observers

To the TNO Observers Community:

Following on the successful exploration of the dwarf planet Pluto, its small satellites, Charon, and the classical TNO Arrokoth, new spacecraft mission concepts are being studied to again target the dwarf planets and minor bodies of the trans-Neptunian region. One such mission concept is the Interstellar Probe, currently being studied by the Johns Hopkins University Applied Physics Laboratory (APL), to explore the outer heliosphere and the local interstellar medium, and it could include a planetary flyby. The following TNO dwarf planets are high-priority exploration targets for their size, likely geophysical complexity, compositional heterogeneity, and their relatively low ecliptic latitude, which makes them easier to target than higher latitude targets. To avoid implied bias, they are presented in alphabetical order:

  • 2002 MS4
  • Eris
  • Gonggong (2007 OR10)
  • Ixion
  • Orcus
  • Pluto
  • Quaoar
  • Sedna
  • Varda
  • Varuna

Due to the fast speed of an Interstellar Probe (>40 au in ~6 years or ~36 km/s), and thus the difficulty in changing trajectories en route, it is imperative that orbit solutions for these potential targets be well-constrained by the potential start of a mission in the early 2030s. To this end, we ask you to consider the following:

  • Processing imaging data in-hand and submitting astrometry to the Minor Planet Center (MPC). Filling in gaps in the MPC astrometry of these targets would further decrease their orbital uncertainties.
  • Considering imaging these targets as back-up observations for your future observing programs. Such observations could fill time while waiting for a target to rise or while waiting for usable weather conditions. Astrometry from these observations would help to extend the time baseline and thus decrease orbital uncertainties.
  • Astrometry from occultations are high-priority measurements. New, high-precision observations represent the best means of reducing orbital uncertainties.

Such observations will help pave the way for TNO dwarf planet flybys by an Interstellar Probe and/or other future missions to the trans-Neptunian region.

For the Interstellar Probe Concept Study,

Kirby Runyon & Bryan Holler
Lead and Deputy Lead for Planetary Science on Interstellar Probe

Kirby Runyon  |  Bryan Holler