Young magnetic star sports carbon monoxide ring
by Phil Unsworth
for Astronomy Now
Posted: 24 January 2012
A team of astronomers has discovered an unusually defined ring of carbon monoxide around a young star, raising questions regarding the stages in solar system formation.
The star, V1052 Cen, sits in the constellation Centaurus approximately 700 light years from Earth and has been under study by an international team of scientists using the European Southern Observatory's Very Large Telescope. The team, which includes Charles Cowley, professor emeritus at the University Of Michigan, and Swetlana Hubrig of the Leibniz Institute for Astrophysics Potsdam, Germany, has discovered a well-defined ring of gas surrounding the star.
Artist's impression of a young star surrounded by a dense disc of gas and dust arranged in defined rings. Image:NASA/JPL-Caltech.
“What's different about this ring is that it is shaped more like a rope than a dinner plate,” says Cowley. “It's exciting because this is the most constrained ring we've ever seen, and it requires an explanation. At present time we just don't understand what makes it a rope rather than a dish.”
The carbon monoxide ring sits at the equivalent distance from its star as the Earth is from our Sun. Carbon monoxide is often detected around young stars but is usually spread throughout its protoplanetary disc – the rotating disc of dense gas and dust that surround a star – before collapsing into the planet-building phase of solar system evolution.
Other unique attributes of V1052 Cen were spotted in 2008, including the observation of a very strong magnetic field, and an extremely slow rotation compared with other similar stars. Knowledge of how the protoplanetary disc, the host star and the magnetic field interact with each other is invaluable when trying to understand the formation and past evolution of a solar system – as well as the chain of events that lead to the formation of our own Solar System – and the team hopes that V1052 Cen's sharply defined ring will aid this.
The team speculate that magnetic fields may hold the ring in place, or alternatively that 'shepherding planets' are reigning it in like several of Saturn's moons control certain planetary rings. But there are still many unanswered questions, and Cowley asks, “why do turbulent motions not tear the ring apart? How permanent is the structure?”
Hubrig suspects that the gaseous ring cannot be pure carbon monoxide. “Calculations must be made to estimate the total amount of mass in the ring," she says. "This information will become part of attempts to model the structure, examine rates of heating and cooling, that will give some idea of how permanent the structure may be.”
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