This is how Haumea was formed, one of the rarest objects in the Solar System

Oct. 28 () –

Using computer simulations, NASA scientists have pieced together how the dwarf planet Haumea in the Kuiper Belt it became one of the most unusual objects in the solar system.

About the size of Pluto, Haumea is strange in several ways. It spins faster by far than anything else its size, turning on its axis in just four hours. Due to its fast spin, Haumea is shaped like a deflated American football instead of a sphere.. Its surface, made up largely of water ice, is unlike almost any other surface in the Kuiper Belt, except for a dozen “siblings” that have similar orbits to Haumea and appear to be related to it. constituting the only known “family” of objects in the Kuiper belt.

“How did something as strange as Haumea and her family come about?” said it’s a statement Jessica Noviello, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

This question inspired Noviello and his colleagues to turn to computer models that could theoretically take Haumea apart and rebuild it from scratch to understand the chemical and physical processes that shaped it.

“Explaining what happened to Haumea forces us to put time limits on all these things that happened when the solar system was forming, so it begins to connect everything in the solar systemsaid Steve Desch, a professor of astrophysics at Arizona State University in Tempe, who worked with Noviello and other colleagues on the modeling experiment described in Planetary Science Journal.

“Haumea has a lot of weird and cool parts,” Desch said, “and trying to explain them all at once has been a challenge.”

Haumea is too far away to measure accurately through a ground-based telescope, and no space mission has yet visited it, so data is sparse. Therefore, to study Haumea (and other little-known worlds), Scientists use computer models to make predictions that fill in the gaps.

The researchers started by inputting just three pieces of information into their models: Haumea’s estimated size and mass, and his fast four-hour “day.”

The models yield a refined prediction of Haumea’s size, its overall density, and the density and size of its core, among other features. Noviello then plugged this information into mathematical equations that helped her calculate the amount of ice on Haumea and the volume of the dwarf planet. In addition, he calculated how Haumea’s mass is distributed and how that affects its spin.. With this information in hand, he sought to simulate billions of years of evolution to see what combination of characteristics of a baby Haumea would evolve into the mature dwarf planet it is today.

“We wanted to understand Haumea fundamentally before going back in time,” Novello said.

Scientists assumed that the Haumea baby was 3% more massive to account for the family members that were once part of it. They also assumed that Haumea probably had a different spin rate and was larger in volume. They then slightly changed one of these features at a time in their models, such as adjusting Haumea’s size up or down, and ran dozens of simulations to see how small changes in its early years would influence Haumea’s evolution. When the simulations returned results that resembled present-day Haumea, the scientists knew they had landed on a story that matched reality.

Based on their model, Noviello and his colleagues hypothesize that when the planets were first forming and everything was spinning around the solar system, Haumea collided with another object. Although this impact would have dislodged pieces, Noviello and his colleagues suggest that these pieces are not the Haumean family we see today, as other scientists have proposed. An impact so powerful, they say, it would have shot down pieces of Haumea in much more dispersed orbits than the family members have.

The Haumean family we see today instead came later, when the dwarf planet’s structure was taking shape: Rocky, dense material settled in the center while lower-density ice rose to the surface, Desch said, ” And when you concentrate all the mass towards the axis, it decreases the moment of inertia, so Haumea ended up spinning even faster than it does today.” Fast enough, the scientists calculated, that ice broke off the surface forming the Haumean family.

Meanwhile, Haumea’s rocks, which, like all rocks, are slightly radioactive, generated heat that melted some ice, creating a subsurface ocean (which no longer exists), found paper co-author Marc Neveu, a researcher NASA’s Goddard. The water soaked into the rocky material in central Haumea and caused it to swell into a large core made of clay, which is less dense than rock. The larger core increased the moment of inertia and thus slowed Haumea’s spin to its current speed.