Ex-lands in the cosmic dust
It was a star similar to the Sun but much more “dusty”, the first scientific objective LBTI interferometer installed at the Large Binocular Telescope, of which Italy with the INAF is a partner. Excellent results: the tool has allowed us to study with great accuracy the distribution of dust around the Astra. LBTI will be crucial to identify the best star where we directly observe exoplanets like Earth.
Look for extrasolar planets is hardly a breeze. Locate then, these include those similar in composition and mass to Earth, it is even more. If we restrict even more images only to exo-lands in the habitable zone, the region around a star that is, where there are conditions to find liquid water, the matter is further complicated.
Among the many observational limits which must necessarily deal astronomers in their investigations, especially for the direct observation of exoplanets, one can be decisive: the annoying presence of dust around their parent stars. It is present in any planetary system but, if excessive, can make it impossible to identify planets.
To understand how much dust there is around systems potentially favorable to host exo-Terre and its distribution, especially in their zone of habitability, today astronomers have more weapons: the instrument LBTI (LBT Interferometer), installed at the Large Binocular Telescope in Arizona, of which Italy with the INAF is one of the international partners. LBTI combines the signals collected from each of the two main mirrors 8.4 meter diameter LBT to obtain detailed images in the infrared, where the band is produced the largest amount of radiation from interplanetary dust of extrasolar systems.
For the first time this instrument was tested to investigate the distribution of dust in the system Eta Corvi, a star-sized solar, known to be unusually ‘dusty’: around it there is a quantity of particles 10,000 times higher than that found in our planetary system. A property which may be due to a recent impact of celestial bodies in the regions closer to the star. The findings, published in the journal The Astrophysical Journal, show that, thanks to the excellent operation of LBTI, the dust appears much closer to the star than of thought, arranging themselves between the star and its zone of habitability.
“With LBTI, we are finally able to know how the dust is distributed around stars,” said Phil Hinz, Principal Investigator of the instrument. “Eta Corvi is not a good candidate for any direct observations of exoplanets in orbit around it, but it shows the quality of LBTI: we are beginning to understand the structure of planetary systems like never before.”