Post 8879

Very Large Telescope: Powerful Eyes on the Sky


In 2004, a team of European and American astronomers studying the TW Hydrae Association, a group of very young stars and other objects, spotted a red speck of light near one of the association’s brown dwarfs. The object was more than 100 times fainter than its parent star. Further observations confirmed that it was an exoplanet orbiting its star at 55 times the Earth-sun distance.

“Our new images show convincingly that this really is a planet, the first planet that has ever been imaged outside of our solar system,” ESO astronomer Gael Chauvin said in a statement.

In 2008, a team of scientists used the VLT to discover and image an object near the star Beta Pictoris. Most directly imaged exoplanets lie far from their stars, past where Neptune would orbit, where stellar light is dimmer. In contrast, the planet Beta Pictoris b lies much closer, where Saturn would orbit.

“Direct imaging of extrasolar planets is necessary to test the various models of formation and evolution of planetary systems,” researcher Daniel Rouan said in a statement. “But such observations are only beginning. Limited today to giant planets around young stars, they will in the future extend to the detection of cooler and older planets, with the forthcoming instruments on the VLT and on the next generation of optical telescopes.”

Spin class

Researchers also used the VLT to determine how fast Beta Pictoris b is spinning, clocking the massive planet almost 62,000 mph (100,000 km/h) at its equator. In comparison, Earth’s equator spins at only 1,056 mph (1,700 km/h), while Jupiter travels at about 29,000 mph (47,000 km/h). This was the first time an exoplanet’s rotation rate had been determined.

ESO/Stéphane Guisard

The sky appears to rotate above ESO’s Very Large Telescope in this long exposure. The star trails curve away from the celestial equator in the middle of the photo, where the stars seem to move in a straight line.

“It is not known why some planets spin fast and others more slowly,” researcher Remco de Kok said in a statement. “But this first measurement of an exoplanet’s rotation shows that the trend seen in the solar system, where the more massive planets spin faster, also holds true for exoplanets. This must be some universal consequence of the way planets form.”

The private organization Breakthrough Initiatives has enlisted the help of the VLT to hunt for planets around Earth’s closest star, Proxima Centauri. After helping to fund an upgrade to an existing instrument on the VLT, Breakthrough Initiatives will receive time for a “careful search” of the Proxima Centauri system for new planets. The improvement in the VLT Imager and Spectrometer for Mid Infrared instrument will equip it with a coronagraph, which blocks much of the light from a star, as well as an adaptive optics system to correct for distortions in starlight caused by Earth’s atmosphere. The upgrade is scheduled to be completed in 2019.

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