Webb observes {asteroid} Chariklo's rings during occultation (earthsky.org)

[eppur_se_muova]

Posted by Paul Scott Anderson

February 3, 2023

On January 25, 2023, NASA said in a blog post that the Webb space telescope has achieved another milestone. It observed the thin rings of Chariklo – the first asteroid known to have rings – a small icy body more than 2 billion miles (3 billion km) from Earth. That’s out past Saturn.

Webb did this by looking at Chariklo during a stellar occultation, where it passed in front of a distant star from Earth’s point of view. Webb saw the star blink not only as it passed behind the asteroid, but also as it passed behind Chariklo’s rings.

Chariklo is the largest known of the Centaur asteroids, which orbit the sun between Saturn and Uranus.

It should be noted that the results discussed here are part of Webb’s “science in progress” and haven’t yet been peer-reviewed. But they do provide a new, tantalizing glimpse of a ring system that some scientists previously doubted even could exist.
***
more: https://earthsky.org/space/chariklos-rings-webb-telescope-stellar-occultation/?utm_source=EarthSky+News

[Igel]

1. Saw this.

One said such a ring couldn't form, being outside the Roche limit. (And got it wrong.)

It did form. Did the object's mass change, so the RL moved?

Did gravity pull the ring into an orbit, and the ring's extended but our instruments didn't grog that it's sort of a small-scale equivalent of a protoplanetary disk? Did the minor planets just have enough gravity to attract the dust and ice granules?

Intriguing. Interesting.

But sometimes two similar things have two different origins. Not Occam's-friendly, but sometimes the outlier is an "entity" that needs to be dealt with.