Titan, the largest moon of Saturn and one of the most fascinating places in the solar system, is a world of rain, rivers, lakes and seas. Unlike Earth though, this alien hydrological cycle is composed of liquid methane rather than water, since the temperatures on Titan are far colder than even at the poles of our own planet.
It had long been theorized, however, that liquid water could actually exist on Titan – underground. Gravitational tugging from Saturn could create enough heat inside Titan to maintain a layer of water, similar to that on another Saturn moon, Enceladus and one of Jupiter’s moons, Europa (and possibly others as well). Literally, an underground ocean.
Some of the most beautiful images of our solar system have come from the Cassini spacecraft orbiting Saturn. Here is another new one, taken on March 12, 2012. It shows two of Saturn’s fascinating moons, Titan (in the background) and Enceladus (in the foreground) along with Saturn’s rings, seen here very obliquely, almost edge-on.
For the first time, astronomers have found a ring system orbiting another star that seems to be similar to the rings of Saturn in our own solar system. It encircles a low-mass object which orbits the star, but it isn’t clear yet if that object is a planet, a very low-mass star or a brown dwarf star.
The scientists used data from the international SuperWASP (Wide Angle Search for Planets) and the All Sky Automated Survey (ASAS) project to study the light curves of young Sun-like stars in the Scorpius-Centaurus region of our galaxy.
This star, 1SWASP J140747.93-394542.6., is about 420 light-years away. It is similar in mass to the Sun, but is much younger, only about 16 million years old.
The ring appears to be a multi-ring system, with at least three or four rings and two or three gaps, another similarity to Saturn’s rings. These are much larger however; Saturn’s rings are a few hundred thousand kilometres across, while these ones are tens of millions of kilometres.
According to Eric Mamajek, Assistant Professor of Physics and Astronomy at the University of Rochester, “When I first saw the light curve, I knew we had found a very weird and unique object. After we ruled out the eclipse being due to a spherical star or a circumstellar disk passing in front of the star, I realized that the only plausible explanation was some sort of dust ring system orbiting a smaller companion—basically a ‘Saturn on steroids.’ We suspect this new star is being eclipsed by a low-mass object with an orbiting disk that has multiple thin rings of dust debris.”
He continued: “This marks the first time astronomers have detected an extrasolar ring system transiting a Sun-like star, and the first system of discrete, thin, dust rings detected around a very low-mass object outside of our solar system. But many questions remain about what exactly has been discovered.”
If the object is less than 13 MJ (Jupiter masses), it is most likely a planet. If however it is between 13 MJ and 75 MJ, than it is probably a brown dwarf star.
Mamajek says that more definite conclusions about these rings will take another couple of years or so of analysis. Finding other ones would of course also be helpful.
Saturn, with its majestic rings, is one of the most beautiful places in the solar system. Jupiter, Uranus and Neptune also all have rings, albeit not as striking as Saturn’s. As we continue to find exoplanets by the thousands, how many of those may also be graced by rings? There might be a wide variety of ringed planets out there, all beautifully unique.
The findings will be published in an upcoming issue of the Astronomical Journal.
Saturn’s tiny moon Enceladus was the centre of attention for the Cassini spacecraft again last week, with beautiful new photos being released of the moon and its water vapour geysers erupting from the south pole. Some views show surface detail on the moon, some are of the geysers themselves and there is a very nice shot of Enceladus silhouetted against Saturn and its rings in the background. There is even a dual ultraviolet stellar occultation in which two of the stars in the belt of the constellation Orion are seen shining through the plumes! Even though these are still raw, unprocessed images, they again capture the beauty of Enceladus and the Saturnian system…