Thursday, April 30, 2015

LBT takes a close look at a lava lake on Jupiter's moon Io

With the first detailed observations through imaging interferometry of a lava lake on a moon of Jupiter, the Large Binocular Telescope Observatory places itself as the forerunner of the next generation of Extremely Large Telescopes. 

Io, the innermost of the four moons of Jupiter discovered by Galileo in January 1610, is only slightly bigger than our own Moon but is the most geologically active body in our solar system. Hundreds of volcanic areas dot its surface, which is mostly covered with sulfur and sulfur dioxide. 

The largest of these volcanic features, named Loki after the Norse god often associated with fire and chaos, is a volcanic depression called patera in which the denser lava crust solidifying on top of a lava lake episodically sinks in the lake, yielding a rise in the thermal emission which has been regularly observed from Earth. Loki, only 200km in diameter and at least 600 million km from Earth, was, up to recently, too small to be looked at in detail from any ground based optical/infrared telescope.


Io seen by LBT (left) on 2013 December 24 (left) compared to a USGS map (right) based on images from NASA’s Voyager 1 and 2 missions (acquired in 1979) as well as the Galileo orbiter (1995-2003).

Credit: LBTO-USGS
With its two 8.4 m mirrors set on the same mount 6 m apart, the Large Binocular Telescope (LBT), by combining the light through interferometry, provide images at the same level of detail a 22.8 m telescope would reach. Thanks to the Large Binocular Telescope Interferometer (LBTI), an international team of researchers was able to look at Loki Patera, revealing details as never before seen from Earth; their study is published today in the Astronomical Journal (link here).

The LBT image of Loki Patera (orange) laid over a Voyager image of the volcanic depression.The emission (in orange color) appears spread out in the north-south direction due to the telescope point-spread function; it is mainly localized to the southern corners of the lake. Credit: LBTO-NASA

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