Astronomers don’t come across as a sentimental bunch, but a group of them in Chile using the Very Large Telescope (VLT) and its Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) may feel like passing around cigars and holding a shower after becoming the first astronomers ever to watch a planet being born. Is it a boy, girl or binary?

“The twist and its apparent orbital motion could well be the first direct evidence of a connection between a protoplanet candidate and its manifestation as a spiral imprinted in the gas and dust distributions.”

That’s the ‘birth announcement’ of the baby planet born to the star AB Aurigae in the Auriga constellation, 520 light-years from Earth. The study, published in the journal Astronomy & Astrophysics, was led by astronomer Anthony Boccaletti from the Observatoire de Paris at PSL University in France. AB Aurigae was selected for this research because of its “twist” – an anomaly in an arm of the spiral disk composed of dust and gas that circles a star prior to the early stages of planet formation. While astronomers have observed these disks before around other young stars, they’ve never had the SPHERE instrument, which provided the sharpest and deepest images ever of the mysterious twist.

Was it like this?

“SPHERE has delivered the deepest images ever obtained for AB Aur in scattered light. Among the many structures that are yet to be understood, we identified not only the inner spiral arms, but we also resolved a feature in the form of a twist in the eastern spiral at a separation of about 30 au. The twist of the spiral is perfectly reproduced with a planet-driven density wave model when projection effects are accounted for.”

The research was almost too easy with SPHERE. The ‘twist’ was exactly what models showed would precede a planet’s formation in a location that would be ideal for such a planet – in this case, about the same distance from AB Urigae as Neptune is from the Sun. Co-author Anne Dutrey from the Astrophysics Laboratory of Bordeaux (LAB) in France tells Science Daily how this twist formed.

“It corresponds to the connection of two spirals — one winding inwards of the planet’s orbit, the other expanding outwards — which join at the planet location. They allow gas and dust from the disc to accrete onto the forming planet and make it grow.”

Is this exciting or what? All we need now is a baby picture. Well, here it is, courtesy of European Southern Observatory (ESO). The baby is in the bright yellow twist.

This is believed to be the first observation of the formation or birth of an exoplanet. Now that astronomers know what to look for, they’re confident more will be found with SPHERE and the 39-meter (130-foot) Extremely Large Telescope, currently under construction in Chile.

So … boy, girl or binary? Let’s just say the astronomers are glad that the baby is healthy and are busy picking a neutral name. Let’s just hope it’s not Pat.

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