Exoplanet Observed Using Light From Optical Telescopes

Exoplanet Observed Using Light Combined From Optical Telescopes
Image Credit: ESO

For the first time in history an exoplanet has been observed using optical interferometry. The process involved combining the light from multiple individual telescopes to reveal a single target in greater detail than any single telescope could produce. The research was carried out by the European Southern Observatory’s (ESO) Very Large Telescope (VLT) array in Chile, using four individual telescope with 8.2m meter mirrors. The result is equivalent to using a single optical telescope with a 100 meter (328 feet) diameter mirror.

Around 4000 Exoplanets Observed

Almost 4,000 exoplanets have been discovered to date. Of these, 2,682 have been detected by NASA’s Kepler space telescope; the original exoplanet hunter telescope which was eventually decommissioned on Nov. 15, 2018 after a decade of operation. It was subsequently replaced by the Transiting Exoplanet Survey Satellite (TESS) launched on April 18, 2018. The instrument uses lenses, sensors and electronics to find transiting exoplanets.

ESO’s GRAVITY Instrument

For the first time ever, the European Southern Observatory’s GRAVITY instrument has been used to to directly observe an exoplanet using optical interferometry. As astronomer researcher Sylvestre Lacour from the Observatoire de Paris explains:

“GRAVITY can use ESO’s Very Large Telescope’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 Very Large Telescope Interferometer — that collects and precisely disentangles the light from HR 8799e’s atmosphere and the light from its parent star.”

Most Detailed Look Ever At An Exoplanet

Despite the number of exoplanets discovered, our understanding of their atmospheres continues to be very limited. This naturally makes it more difficult to determine where to focus our search for extraterrestrial life.

Subsequent findings by GRAVITY, however, have resulted in the most detailed look ever at an alien world. The ‘super-Jupiter’ type planet HR 8799e is just 30 million years old. This is young enough to provide scientists with a glimpse into planetary formation. It orbits a young star located around 129 light-years away in the constellation of Pegasus.

Initial findings reveal a planet orbiting its sun 14.5 times further away than the Earth is from our Sun. It also takes around 45 years to complete an orbit. Despite its distance, the planet has a strong greenhouse effect and has an inhospitable temperature of 1,611 degrees Fahrenheit (877 degrees Celsius). Elaborating further, Sylvestre Lacour explains:

“Our analysis showed that HR 8799e has an atmosphere containing far more carbon monoxide than methane – something not expected from equilibrium chemistry. 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.”

Exciting Time For Exoplanet Hunting

The innovative method of interferometry using optical telescopes opens up the possibility of its effective use by astronomers to explore all kinds of nearby solar systems. They will then be able to study in greater detail any subsequent exoplanets they do discover. In the process, heralding in a new and exciting era for exoplanet hunters.

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