Very Large Telescope sees signs of planet birth in action

Could the disc of gas and dust surrounding a star 335 light years away be the construction yard for a planet?


An artist’s impression of a gas giant planet forming in the disc around the young star HD 100546.

According to observations made by ESO’s Very Large Telescope (VLT), an alien world may have been caught in the act of forming and, if proven true, could be hailed as the first direct observation of planetary construction, greatly improving our understanding of how planets are born.

The planetary candidate, which was picked up as a faint blob by the VLT’s adaptive optics, is thought to be studded in a disc, chock-a-block with gas and dust and surrounding a young star – designated HD 100546 – which rests a distance of 335 light years from Earth. In astronomical terms, this short distance can be regarded as within our cosmic backyard.

It is our current understanding that planets are constructed from the leftover gas and dust remaining after the formation of a star. Observing at near-infrared wavelengths, Sascha Quanz at the ETH Zurich Institute of Astronomy and his team were able to strongly suggest that the glowing object could be a planet, adding to previous suggestions that a giant world exists around the highly scrutinised HD 100546.

“From the data we have in our hands, the brightness is best explained with an object that is currently accreting a lot of material,” Quanz says, who is confident that this growing clump of gas will become a gas giant planet like our gigantic neighbour Jupiter, despite having no direct measurements of its mass.

“This ‘runaway’ gas accretion phase is an early evolutionary stage for gas giant planets, similar to Jupiter. Concerning the question [as to] whether it is a hot Jupiter or more like our Jupiter, it is certainly the latter,” he tells All About Space. “It orbits at just over six billion miles where the insulation from the star is very low and hence – once the object is fully formed and the disk is gone – it will start cooling quickly.”

Given that the 2.4 solar mass star of an average temperature of roughly 10,200 degrees Celsius is more luminous than our Sun, this orbital distance corresponds to roughly over one billion miles in our Solar System – which lands us somewhere between Saturn and Uranus.

While Quanz and his team are optimistic that what they have uncovered is a planet in the process of forming, further research must be conducted before they can say for certain. Perhaps then we can get a more definite figure of the baby planet’s age which, the researchers admit, is tough to be sure of at this stage, but it cannot be very much. “Planet formation models predict this runaway gas accretion phase to be comparatively short,” Quanz says.

“Exoplanet research is one of the most exciting new frontiers in astronomy and direct imaging of planets is still a new field greatly benefitting from recent improvements in instruments and data analysis methods,” adds Adam Amara, also at ETH Zurich. “In this research we used data analysis techniques developed for cosmological research showing that cross-fertilization of ideas between fields can lead to extraordinary progress.”

You can follow Gemma on Twitter @Gemma_Lavender

Image courtesy of ESO/L. Calçada

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