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Discovery of 18 exoplanets similar to Earth

Credit: NASA/AMES/SETI

Recently, a new more sensitive algorithm re-immersed itself in the data collected by Kelper.  This algorithm has pulled our eighteen new exoplanets with the majority showing similarities to Earth.  

After running out of fuel, the Kepler spacial telescope decisively finished its mission last October after almost ten years in orbit. During its activity, this telescope discovered thousands of exoplanets and its work is still paying off!  Thanks to a newly released algorithm, a team of German astronomers have discovered 18 new exoplanets which were hidden in Kepler’s data.  This significant discovery will allow researchers to now establish followup studies.  Two separate studies have been published in the Astronomy & Astrophysics journal which can be found by clicking here and here.

Hunting with the best viewfinder

The Transit Method is one of the most commonly used methods when “chasing exoplanets”.  The idea involves observing stars and looking for possible reductions in luminosity which appear suddenly.  This situation normally arises when one or several passing planets pass between the star and the telescope, and as a result block part of the light.  However strong drops in brightness are generally needed to reveal these planets.  As a result, it is no surprise that previously discovered exoplanets are generally similar to giant gas-based planets like Jupiter or Saturn or icy giants like Neptune or Uranus.

In other words, until now our instruments have been calibrated to detect very large planets.  On paper, the discovery of these giant planets is interesting but perhaps not as much as those worlds that closely resemble our own.  Indeed, only our planet is known to harbour life.  Based on this point of view, researchers have developed a new, more sensitive method.

Eighteen new hidden worlds

In general the method is based on the same principle. However instead of looking for abrupt changes, the method takes into consideration more gradual changes of luminosity which are produced when small planets pass in front of a star.  If these changes are regular, it is highly likely that a planet is in orbit.

Researchers immersed themselves once more in the Kepler’s previously collected data between 2014 and 2018 to test this new algorithm.  During this period, the telescope identified 517 stars surrounded by at least one exoplanet.   By carrying out a new analysis using this new method, researchers were able to give themselves every chance of detecting the presence of smaller worlds that resemble our own planet.   The research was successful, as eighteen new planets were brought to light! .

exoplanètes
The size of the newly discovered planets in comparison with Earth and Neptune. Credits: NASA/JPL (Neptune), NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring (Earth), MPS/René Heller

For the time being little is known about these exoplanets.  Nevertheless, the smallest of the lot is only two-thirds of the size of Earth.  On a side note, this is in fact the second smallest exoplanet detected to date.  Two other planets are also smaller than our own, while the other fifteen are slightly bigger.

One of the them particularly interests researchers as its surface temperature could allow liquid water to be sustained on the surface.  This means that it could provide the right conditions for life although this is of course not the only determining factor.

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