One proposal offers a unique method to directly image ExoEarths, or rocky worlds around nearby stars.<\/em><\/p>\n It\u2019s the holy grail of modern exoplanet astronomy. As of writing this, the count of known worlds beyond the solar system stands at 6,520. Most of these are \u2018hot Jupiters,\u2019 large worlds in tight orbits around their host star. But what we\u2019d really like to get a look at are \u2018ExoEarths,\u2019 rocky worlds (hopefully) like our own.<\/p>\n <\/p>\n Now, a recent study out of the University of Paris, the European Southern Observatory (ESO) and the University of Cambridge entitled Exoplanets in Reflected Starlight with Dual-Field Interferometry: A Case For Shorter Wavelengths and a Fifth Unit Telescope at VLTI\/Paranal<\/em> suggests a method to do just that in the coming decade. This would involve one the most massive telescope complexes ever built: the Very Large Telescope. Based at Paranal Observatory in Chile, this array consists of four 8.2-metre telescopes working in concert via a method known as interferometry. The study advocates adding a fifth telescope, giving the VLT the capacity to see Jupiter-sized worlds shining directly in the host star\u2019s light\u2026 and with a few key upgrades, the new and improved VLT could perhaps image \u2018ExoEarths\u2019 directly.<\/p>\n Interferometry is the method of using superimposed waves collected from two telescopes to merge a signal into one image. This method allows for a resolution equivalent to the baseline between the two collecting instruments, bypassing the need for one enormous telescope. Long baseline radio interferometry can span continents, and there are plans to move the technique into space. Interferometry at visual wavelengths is a tougher proposition, one that\u2019s just reaching its true potential.<\/p>\n Dual Field Interferometry uses the technique to simultaneously focus on two narrow fields in context within a larger field. One field is centered on the host star, and one on the target exoplanet. This can then minimize (subtract) photon shot noise from the primary, allowing for a clear view of the target world.<\/p>\n \u201cWith this technique, at the VLTI, we have a resolution equivalent to having a telescope of 130 meters,\u201d lead author on the study Sylvestre Lacour (University of Paris) told Universe Today<\/em>. \u201cThis allows us to distinguish the exoplanet\u2019s light from the contamination by the stellar light, allowing to detect exoplanets very close to the star.\u201d<\/p>\n \u201cThe term \u2018dual\u2019 in dual interferometry comes from the fact the we are observing at the same time the exoplanet and the star with the optical interferometer,\u201d says Lacour. \u201cThis is necessary to be able to probe at the same time the phase of the stellar light and the phase of the exoplanet light, to be able to distinguish the two. By \u2018phase\u2019 I mean the phase of the electric field entering the interferometer.\u201d<\/p>\n The method is already being applied to reveal nearby worlds. \u201cWe typically observe exoplanets at a few tens of parsecs,\u201d says Lacour. \u201cThey are massive exoplanets, more massive than Jupiter (between 4 and 10 Jupiter masses), and they are young, less than 50 million years (old). You can look for the results for the GRAVITY collaboration, operating the GRAVITY instrument at Paranal.\u201d<\/p>\nPioneering Dual-Field Interferometry <\/h2>\n
![\"GRAVITY\"](\"https:\/\/www.universetoday.com\/wp-content\/uploads\/2024\/06\/ann15061c-1024x576.jpg\")
The Hunt for ExoEarths<\/h2>\n