Giant iron rings might hold clues about young solar systems

By the time humans got onto the scene, the Solar System had been pretty well formed for around 4.5 billion years.

Although this is very good for life on the planet, it does mean that to find out the intricacies of how it formed, astronomers have to look elsewhere.

A new study has done just this for a young star called HD 144432 just 500 light years away from Earth, discovering three iron rings or discs, and potentially two planets hiding in between. 

A paper looking at the findings has been published in the journal Astronomy & Astrophysics.

“When studying the dust distribution in the disc’s innermost region, we detected for the first time a complex structure in which dust piles up in three concentric rings in such an environment,” says Dr Roy van Boekel, a researcher at the Max Planck Institute for Astronomy in Germany.

“That region corresponds to the zone where the rocky planets formed in the Solar System.”

Using the European Southern Observatory’s Very Large Telescope Interferometer (VLTI), the researchers found the first ring corresponds to Mercury’s orbit, the second ring is close to Mars’ and the third roughly sits in Jupiter’s orbit.

This is important because this zone is rich in dust, which is what forms rocky planets like Earth, Mars and Venus. 

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A diagram showing the location and type of rings in the system.  Credit: J. Varga et al. / MPIA

While other rings like this had been shown before, HD 144432 is the first-time scientists have seen such a complex ring system so close to its host star.

However, it’s worth pointing out that the system is not likely to be forming Earth sized planets – the two rings’ sizes suggest the planets could have masses the size of Jupiter.

“We think that the HD 144432 disk may be very similar to the early Solar System that provided lots of iron to the rocky planets we know today,” says van Boekel.

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“Our study may pose as another example showing that the composition of our Solar System may be quite typical.”

While HD 144432 will need a keen eye kept on it to see how it evolves, there are also more solar-like systems that the researchers want to investigate. 

“We still have a few promising candidates waiting for the VLTI to take a closer look at”, says van Boekel.

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