Young solar systems shaped by growing planets

Observations of newborn stars have revealed how young planets influence the shape of the discs from which they grow.

These three planetary discs have been observed with the SPHERE instrument, mounted on ESO’s Very Large Telescope. The observations were made in order to shed light on the enigmatic evolution of fledgling planetary systems. The central parts of the images appear dark because SPHERE blocks out the light from the brilliant central stars to reveal the much fainter structures surrounding them.

Left to right, the stars HD 97048, HD 135344B and RX J1615, observed as part of new studies into how growing planets shape the discs surrounding young stars Credit: ESO

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Young planets sculpt and shape the protoplanetary discs in which they grow around newborn stars, in new images released by the European Southern Observatory (ESO).

The observations were made using the SPHERE instrument on ESO’s Very Large Telescope and show how growing planets interact with the discs of gas and dust surrounding their host stars to carve them into vast rings and spiral shapes.

The discs are known as protoplanetary discs and contain the dust and gas that eventually coalesces to form young, orbiting planets.

The discs can extend for thousands of millions of kilometres into space.

While astronomers know that planetary systems may eventually form from these discs, the exact process is not clear.

These latest observations can help astronomers learn more about how the growing planets affect the shape of the discs in which they are formed.

Jos de Boer of Leiden Observatory in the Netherlands led a team that looked at RX J1615, a young star about 600 lightyears from Earth in the constellation of Scorpius.

Observations using SPHERE found that the young planets orbiting the star have carved its protoplanetary disc into rings, resembling those around Saturn.

At just 1.8 million years old, this system is relatively young, making the observations a unique insight into the evolution of young planetary systems.

Also at Leiden Observatory, Christian Ginski led a team that observed young star HD 97048 in the constellation of Chameleon, about 500 lightyears from Earth.

The disc around this star has also been sculpted into rings.

These two separate discoveries have increased the number of known, concentric ringed young star systems, as most protoplanetary systems tend to be more asymmetrical.

Such typical asymmetry was observed, however, in the disc around the star HD 135344B about 450 lightyears from Earth.

Observations led by Tomas Stolker of the Anton Pannekoek Institute for Astronomy in the Netherlands revealed a spiral-like structure, thought to be caused by massive young planets that could eventually grow to the size of Jupiter.

Observations also revealed four dark streaks in the disc thought to be shadows caused by the movement of material.

One of these streaks was seen to change in the months between observations, meaning astronomers were able to capture the evolution of the disc in real time.

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This is thought to have been caused by changes occurring in the inner disc regions that cannot yet be directly detected.