synestia

plural synestias

1. astrophysicsA donut-shaped body of vaporized and molten rock formed from the collision of two planet-sized objects.

   The investigation also examined the geochemical consequences of lunar formation resulting from the high-energy collision of proto-planets that created a huge, vaporized, doughnut-shaped object called a synestia.

   2019 April 24, G. Jeffrey Taylor, “Volatile Elements Test Models for the Origin of the Moon”, in Planetary Science Research Discoveries

   2 more examples

   For any rotating planetary body, there is a thermal limit beyond which the rotational velocity at the equator intersects the Keplerian orbital velocity. Beyond this corotation limit (CoRoL), a hot planetary body forms a structure, which we name a synestia, with a corotating inner region connected to a disk-like outer region.

   2017 May 23, SJ Lock, ST Stewart, “The structure of terrestrial bodies: Impact heating, corotation limits, and synestias”, in Journal of Geophysical Research

   For a brief time during its infancy, Earth was a hot, doughnut-shaped blob called a synestia. […] A synestia has an exterior region marked by clouds of molten rock and dust, all at a scorching 2000°C or hotter.

   2017 June 3, Shannon Hall, “Early Earth was a molten doughnut”, in New Scientist, volume 234, number 3128, page 10