A preliminary orbit for the satellite of dwarf planet (136472) Makemake

I present a preliminary orbit for the satellite of dwarf planet (136472) Makemake, based on archival Hubble Space Telescope images taken on 13 days between April 2015 and February 2019. The satellite was detected on twelve of them. A best-fit circular orbit has a period of $18.023 \pm 0.017$ d, a semi-major axis of $22250 \pm 780$ km, and an inclination of $83.7^{\circ} \pm 1.0^{\circ}$ relative to the line of sight. That orbit is nearly edge-on, raising the possibility of ongoing or imminent mutual events between Makemake and its satellite.