The dwarf planet Haumea is one of the alien objects in the solar system. How did it come to this?

There is still a debate raging in some circles whether Pluto should be a planet or not. Ask an astronomer, and their typical answer would be something like – if Pluto is a planet, then there are many other bodies in the solar system that should also be considered as such. One of them is Haumea, a small rock explored in the Kuiper Belt which is one of the strangest large objects. Now a NASA team has a new insight into how it happened.

Since Haumea is so far away, there isn’t much hard data about it. A probe has never visited it, and it is too small and too remote to be properly measured by a terrestrial telescope. The researchers who were interested in it therefore turned to this favorite tool of most astrophysicists: computer models.

Computer models need inputs to make predictions, however, and there are a few weird things we already know about Haumea. One is the speed at which it spins – a day lasts only four hours on its surface, much shorter than the day of any similarly sized object in the solar system. Additionally, he is elongated, somewhat resembling an American football rather than the spherical shape that most bodies of his size take on.

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There is also a “family” present – small balls of what appears to be water ice that float in a similar orbit around Haumea’s main body. A bit like moons, but not considered as such. So how did all this weirdness come about? To figure it out, the researchers had to go back in time — and make some guesses, of course.

It was a two-step process. First, Jessica Noviello, now a postdoctoral researcher at NASA’s Goddard Space Flight Center, developed a model that required only three separate inputs – Haumea’s size, mass, and rotational speed. The results of this first model, such as body core size and density, were then fed into another model which was used as an iterative basis to find a creation process that reflected what Haumea looks like now.

Introducing small changes in these input parameters of the final simulation resulted in a set of expected results, which could be compared to the measured reality. But it also highlighted some interesting features that likely happened when Haumea was formed.

First, it was probably hit by a massive object early in its history. Hence the dramatic twist. But, while the impact would have toppled parts of Haumea, it would likely have been too violent to simply form the little balls of ice now known as its “family”.

Creating these tiny scoops of ice cream required a second process, which took much longer, but arguably had just as much of an impact. The rapid rotation slid denser rocks into the dwarf planet’s core, and those rocks started doing something unexpected. Since they were, like all rocks, radioactive, they began to melt the water ice that was coagulating on Haumea’s outer shell.

Some of this water then flooded the core, creating a clay-like substance, which the rapid centripetal force then tossed out like a potter, creating the elongated shape we see today. Additionally, some of the icy balls lost their grip on the main body and gently broke apart to form smaller icy bodies that still spin in the same orbit as the parent dwarf planet.

These results are all from simulations at this point, but they make sense both logically and scientifically. However, it will still be some time before more concrete data is collected on Haumea or its Kuiper Belt cousins. Until then, astrophysicists will have to make do with articles like the one by Dr. Noviello and his team recently published in the Planetary Science Journal.

Learn more:
NASA – NASA is studying the origins of a “strange” object in the solar system: the dwarf planet Haumea
Novello et al. – Let It Go: geophysical ejection of Haumea family members
UT – The dwarf planet Haumea
UT – Dwarf planet Haumea has a ring

Main picture:
Screenshot of an interactive 3D model of Haumea.
Credit – NASA Visualization Technology Applications and Development