Let It Go: Geophysically Driven Ejection of the Haumea Family Members

• Published in: The planetary science journal Vol. 3; no. 9; pp. 225 - 243
• Main Authors: Noviello, Jessica L., Desch, Steven J., Neveu, Marc, Proudfoot, Benjamin C. N., Sonnett, Sarah
• Format: Journal Article
• Language: English
• Published: The American Astronomical Society 01-09-2022
• Subjects: Dwarf planets; Kuiper belt; Planetary interior
• ISSN: 2632-3338; 2632-3338
• DOI: 10.3847/PSJ/ac8e03

We present a new model for Haumea’s formation and evolution that relies on geophysical and geochemical data informed from observations of Haumea and meteorites to explain the characteristics of Haumea and its dynamical family. We hypothesize that after the impact of two partially differentiated Kuiper Belt objects, Haumea’s rocky core grew, decreasing its moment of inertia (MOI), spinning it up to the point that icy material was ejected from its surface. This ice, carrying about 3% of Haumea’s mass and 14% of its initial angular momentum, comprises the Haumean dynamical family and the ring system and moons observed today. Later, melted ice hydrated Haumea’s core and it grew, increasing Haumea’s MOI and spinning it down to the modern value. We use the geophysical code
kyushu
to demonstrate that solutions exist for a Haumea in hydrostatic equilibrium at each of these hypothesized stages. Geochemical modeling using the
IcyDwarf
code constrains the formation of Haumea’s core and the creation of the collision family to have occurred after roughly 150–160 Myr of solar system evolution (4.41 ± 0.01 Gyr ago). Hydration of the core was complete by about 0.20 Gyr, but a substantial subsurface ocean with half the mass of Earth’s oceans persisted until it froze at about 0.45 Gyr, making Haumea the solar system’s most distant potential relict ocean world.