First Ring System Around Asteroid

[Ichingcarpenter]

Source: eso

Observations at many sites in South America, including ESO’s La Silla Observatory, have made the surprise discovery that the remote asteroid Chariklo is surrounded by two dense and narrow rings. This is the smallest object by far found to have rings and only the fifth body in the Solar System — after the much larger planets Jupiter, Saturn, Uranus and Neptune — to have this feature. The origin of these rings remains a mystery, but they may be the result of a collision that created a disc of debris. The new results are published online in the journal Nature on 26 March 2014.

The rings of Saturn are one of the most spectacular sights in the sky, and less prominent rings have also been found around the other giant planets. Despite many careful searches, no rings had been found around smaller objects orbiting the Sun in the Solar System. Now observations of the distant minor planet Chariklo as it passed in front of a star have shown that this object too is surrounded by two fine rings.

"We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery — and the amazing amount of detail we saw in the system — came as a complete surprise!" says Felipe Braga-Ribas (Observatório Nacional/MCTI, Rio de Janeiro, Brazil) who planned the observation campaign and is lead author on the new paper.

Chariklo is the largest member of a class known as the Centaurs and it orbits between Saturn and Uranus in the outer Solar System. Predictions had shown that it would pass in front of the star UCAC4 248-108672 on 3 June 2013, as seen from South America . Astronomers using telescopes at seven different locations, including the 1.54-metre Danish and TRAPPIST telescopes at ESO’s La Silla Observatory in Chile , were able to watch the star apparently vanish for a few seconds as its light was blocked by Chariklo — an occultation .

Read more: http://www.eso.org/public/news/eso1410/

[awoke_in_2003]

1. K&R. nt

[Treant]

2. So it's not just planets

that can't clean up after themselves. Good to know.

I wonder if the ring system is temporary or semi-permanent like Saturn's? I'd expect it to be very susceptible to gravitational perturbation, but maybe the asteroid never gets close enough to anything of appreciable size for that to happen.

[Orsino]

3. "Then what's Pluto?" n/t

[shireen]

4. there could be many more out there

This one was found when the asteroid occulted a star (passed in front of a star). By monitoring the light from the star as the asteroid passes in front of it, they likely saw it dip slightly twice before being blocked. So it is a matter of watching other stars being occulted by asteroids to build up a list of ringed asteroids. Pretty cool.

[fascisthunter]

5. Wow... only 250 km in diameter

250 km=155.343 miles

[Laelth]

6. Nifty. k&r n/t

-Laelth

[Ikonoklast]

7. For those interested in Chariklo's orbital ephemeris.

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Chariklo+&orb=1

[sofa king]

8. One of the few things we know about Centaurs...

... Is that they don't stay Centaurs forever. The giant planets are too strong and the orbits of the Centaurs are inherently unstable.

This suggests that Centaurs are fungible, that their numbers are somehow replenished by new Centaurs as the older ones are sent on to their fates.

That in turn suggests that some mechanism is sending asteroids and comets inward.

And what do you know? In just the past month one sky survey found that there can be no other gas giant planets in our solar system--no Planet X--while a second one found yet another dwarf planet orbiting beyond the Kuiper Belt.

So it looks like the Centaurs are resupplied by dwarf planets from the Inner Oort Cloud and beyond. It's easy to guess that on an Internet message board, but a room full of people would have to work years for someone to prove it.