Kuiper Belt dwarf planet has its own ring

[Brian G Turner]

Distant dwarf planet near Pluto has a ring that no one expected

A ring has been found around Haumea, a world more than 2 billion kilometres beyond Pluto. The ring is the most distant ever seen in our solar system.

“This is a landmark discovery,” says Alan Stern at the Southwest Research Institute in Boulder, Colorado. “It’s very exciting.”

Until recently, the only known rings circled giant planets such as Saturn. In 2013, however, astronomers found two rings around Chariklo, an odd little rock about 250 kilometres across between the orbits of Saturn and Uranus. Chiron, one of Chariklo’s neighbours, may also have a ring.

Another interesting point suggests that Haumea may be a fragment from an earlier collision, suggesting it may have been significantly larger:

The far-off world is shaped like an egg, which may result from its whirlwind rotation. Haumea completes a full spin every 3 hours and 55 minutes, whereas the dwarf planet Pluto, which is almost perfectly round, rotates every 6.4 Earth days. Every 24 hours, a resident on Haumea’s equator would see six sunrises and six sunsets. It also has two small moons.

McKinnon suspects that all these traits are linked. He thinks a large object may have hit Haumea, causing it to spin and eject debris that created both the ring and the moons.

This impact would also explain another phenomenon: several other bodies travel on almost the same path around the sun as Haumea and share its composition, having water ice on their surfaces. They could all have been born during the same initial smash-up.

 

[Ursa major]

Some will think it's a good thing that a dwarf planet named after the Hawaiian goddess of childbirth is, at the very least, engaged....