It's not just Saturn and gas giants such as Uranus which have rings in our solar system – as a tiny dwarf planet has just been spotted with its very own.
It's the first dwarf planet beyond Neptune to be spotted with its own ring – and could prove that such rings are not uncommon in the outer solar system.
takyon: Haumea has two known moons as well as this newly discovered ring:
A stellar occultation observed on 21 January 2017 indicated the possibility of a ring system around Haumea. As published in Nature on 11 October 2017, this occultation was confirmed to be a ring, representing the first such ring discovered for a TNO. The ring has a radius of about 2,287 km, a width of ~70 km and an opacity of 0.5. The ring plane coincides with Haumea's equator and the orbit of its larger, outer moon Hi'iaka. The ring is close to the 3:1 resonance with Haumea's rotation.
Haumea is known for its extremely elongated shape, a consequence of its rapid rotation.
The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation (DOI: 10.1038/nature24051) (DX)
(Score: 2) by bzipitidoo on Thursday October 12 2017, @02:43PM (7 children)
Cool, dwarf planets can have moons and rings. If it quacks like a duck... well, you know. This quacks like certain large planets in a solar system.
Maybe a simple semantics trick? Call them all planets, and add a modifier to the big ones, instead of the little ones. Call the big ones "major planets", "super planets", "power planets", or ... well, something.
(Score: 3, Funny) by bob_super on Thursday October 12 2017, @05:11PM (5 children)
Knowing astronomers, it would be "Large Planet, Very Large Planet, Extremely Large planet, 30m planet and Overwhelmingly Large Planet [cancelled]"
(Score: 0) by Anonymous Coward on Thursday October 12 2017, @05:55PM (4 children)
How about they just make it simple, anything that forms a spherical shape due to it's own gravity is a planet. Yes you can exempt stars and derivatives there-of, but you really don't have to. I know I'm asking for too much, these are the same type of people that call the same thing three different things depending on where it actually is.
(Score: 0) by Anonymous Coward on Thursday October 12 2017, @10:23PM (3 children)
I like the current definition that says it has to dominate its orbit and clear out any stuff there.
The International Astronomical Union also specifies that a planet must orbit around only one object (a star).
.
I also like the word planetoid for lesser objects.
.
it's own gravity
it's == it is; it has
its == belongs to it
A pronoun never needs an apostrophe to make it plural. (its, ours, yours, hers, theirs)
-- OriginalOwner_ [soylentnews.org]
(Score: 2) by bob_super on Friday October 13 2017, @12:47AM (1 child)
> I like the current definition that says it has to dominate its orbit and clear out any stuff there.
Almost all major planets have moons and trojans. I don't know why they have a definition that needs extra clarification.
Is it over 90% round, bigger than a breadbox, orbiting a star with an excentricity below 90%, and any objects orbiting it don't bring that system's center of mass outside of the body? It's a planet.
KISS.
(Score: 0) by Anonymous Coward on Friday October 13 2017, @06:39AM
Heh. Yeah.
-- OriginalOwner_ [soylentnews.org]
(Score: 1) by toddestan on Saturday October 14 2017, @05:03PM
Actually, not "a star", but "the Sun". So yes, by definition there are only eight planets in the entire universe.
(Score: 2) by takyon on Thursday October 12 2017, @06:39PM
"Centaurs [wikipedia.org]" can also have rings
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