GRAVITY instrument breaks new ground in exoplanet imaging

GRAVITY instrument breaks new ground in exoplanet imaging
The GRAVITY instrument on ESO's Very Large Telescope Interferometer (VLTI) has made the first direct observation of an exoplanet using optical interferometry. This method revealed a complex exoplanetary atmosphere with clouds of iron and silicates swirling in a planet-wide storm. The technique presents unique possibilities for characterising many of the exoplanets known today. Credit: ESO/L. Calçada

The GRAVITY instrument on ESO's Very Large Telescope Interferometer (VLTI) has made the first direct observation of an exoplanet using optical interferometry. This method revealed a complex exoplanetary atmosphere with clouds of iron and silicates swirling in a planet-wide storm. The technique presents unique possibilities for characterising many of the exoplanets known today.

This result was announced today in a letter in the journal Astronomy and Astrophysics by the GRAVITY Collaboration, in which they present observations of the HR8799e using optical interferometry. The exoplanet was discovered in 2010 orbiting the young main-sequence star HR8799, which lies around 129 light-years from Earth in the constellation of Pegasus.

Today's result, which reveals new characteristics of HR8799e, required an instrument with very high resolution and sensitivity. GRAVITY can use ESO's VLT's four unit telescopes to work together to mimic a single larger telescope using a technique known as interferometry. This creates a super-telescope—the VLTI—that collects and precisely disentangles the light from HR8799e's and the light from its .

HR8799e is a 'super-Jupiter', a world unlike any found in our Solar System, that is both more massive and much younger than any planet orbiting the Sun. At only 30 million years old, this baby exoplanet is young enough to give scientists a window onto the formation of planets and planetary systems. The exoplanet is thoroughly inhospitable—leftover energy from its formation and a powerful greenhouse effect heat HR8799e to a hostile temperature of roughly 1000 °C.

This is the first time that optical interferometry has been used to reveal details of an exoplanet, and the new technique furnished an exquisitely detailed spectrum of unprecedented quality—ten times more detailed than earlier observations. The team's measurements were able to reveal the composition of HR8799e's atmosphere—which contained some surprises.

"Our analysis showed that HR8799e has an atmosphere containing far more carbon monoxide than methane—something not expected from equilibrium chemistry," explains team leader Sylvestre Lacour researcher CNRS at the Observatoire de Paris—PSL and the Max Planck Institute for Extraterrestrial Physics. "We can best explain this surprising result with high vertical winds within the atmosphere preventing the carbon monoxide from reacting with hydrogen to form methane."

The team found that the atmosphere also contains clouds of iron and silicate dust. When combined with the excess of , this suggests that HR8799e's atmosphere is engaged in an enormous and violent storm.

"Our observations suggest a ball of gas illuminated from the interior, with rays of warm light swirling through stormy patches of dark clouds," elaborates Lacour. "Convection moves around the clouds of silicate and iron particles, which disaggregate and rain down into the interior. This paints a picture of a dynamic atmosphere of a giant exoplanet at birth, undergoing complex physical and ."

This result builds on GRAVITY's string of impressive discoveries, which have included breakthroughs such as last year's observation of gas swirling at 30% of the speed of light just outside the event horizon of the massive Black Hole in the Galactic Centre. It also adds a new way of observing exoplanets to the already extensive arsenal of methods available to ESO's telescopes and instruments—paving the way to many more impressive discoveries.

This research was presented in the paper "First direct detection of an exoplanet by optical interferometry" in Astronomy and Astrophysics.


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Journal information: Astronomy and Astrophysics

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Mar 27, 2019
Wow! That's an amazing amount of detailed information from an exoplanet. Never thought this was possible.

Mar 27, 2019
GRAVITY is an impressive instrument. We'll get a lot of data and papers from it, and its follow-ons will get even more. It may even edge out ALMA, which is saying a lot.


Mar 27, 2019
"Our analysis showed that HR8799e has an atmosphere containing far more carbon monoxide.... "We can best explain this surprising result with high vertical winds within the atmosphere preventing the carbon monoxide from reacting with hydrogen...".....The team found that the atmosphere also contains clouds of iron and silicate dust. When combined with the excess of carbon monoxide, this suggests that HR8799e's atmosphere is engaged in an enormous and violent storm.
I wonder if excess Carbon Monoxide reacts with that Iron to create Iron Carbonyl?
https://en.wikipe...carbonyl

And if that Silicon reacts with any excess Chlorine to produce Silicon Chloride?
https://en.wikipe...chloride

Both are volatile, more easily entrained in storm currents bringing the Iron/Silicon into upper atmosphere for easier detection? Would these two compounds create complex 'constant-interchange' chemistry while mixing aloft?

Just passing thoughts. :)

Mar 27, 2019
An excellent find by newly developing technology..
My only disappointment was how young the planet & it's star system are.
From wiki:
... fairly close to its star, lying just between the orbits of Saturn and Uranus in the Solar System. ... HR 8799 e orbits closer to its star than the other three known planets in this planetary system. This planet orbits at an estimated distance of 14.5 AU

Still this raises hopes that we are reasonably closer to the tech needed to detect planets billions of years older.
It would not be unreasonable to speculate if similar duper-gas-giants are able to maintain that degree of internal heating?
That there is an implausible but not entirely impossible opportunity for a habitable moon with an iron-core, surviving long enough to evolve an Alien Biosphere?

It is also possuble that there maybe dwarf-rocky worlds still assembling out of the planetismal-debris-disks?

Mar 29, 2019
I find this very unfortunate that this astounding news was decided to be accompanied by an artist impression image and that this very fact is (was the time I read) not mentioned anywhere in the article.

Mar 29, 2019
I find this very unfortunate that this astounding news was decided to be accompanied by an artist impression image and that this very fact is (was the time I read) not mentioned anywhere in the article.


I think anybody of even moderate intelligence would realise that that is an artist's impression! 129 light years! You think we could get an image like that?

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