The Courier & Advertiser (Perth and Perthshire Edition)
Astronomers’ shock discovery
WITH THEIR planetary rings of cosmic dust, the gas giants of Saturn, Jupiter, Uranus and Neptune are renowned for their interstellar beauty.
Now the surprising discovery of a double-ring system surrounding one of the many small objects in our solar system has captured the imagination of astronomers.
The discovery of the rings around the “centaur” named Chariklo, which has a diameter of about 150 miles, was made by astronomers at St Andrews University in just 20 seconds.
The new research, reported yesterday in the journal Nature, suggests the rings around Chariklo are partly composed of water ice.
Dr Martin Dominik, Royal Society University research fellow in the school of physics and astronomy of St Andrews University said: “We did not even dare to dream about finding a ring, let alone two. That took us by complete surprise, and we actually do not know why they are there.”
The ring system could be detected because Chariklo was predicted to conceal a star on June 3 2013, visible during the night across South America.
Rather than just seeing the light from the star disappearing while Chariklo passes over it, further short interruptions were recorded from seven sites, from which the detailed properties of the ring system could be constructed.
Dr Dominik added: ”Everything happened within just 20 seconds.
“Resolving the rings, which are seven and three kilometres wide respectively, with an eight kilometre gap in between, only became possible by acquiring as many as 10 image frames per second with our telescope in La Silla.”
Dr Dominik is one of the co-leaders of the MiNDSTEp (Microlensing Network for the Detection of Small Terrestrial Exoplanets) consortium, using the Danish 1.54m telescope at the ESO site in La Silla in Chile.
The origin of the rings around Chariklo remains unknown. Whether or not other small Solar system objects have such rings as well remains a matter of speculation.