At this point, we know of 400 planets orbiting stars outside our solar system, but 96% of them are considerably larger than Earth, comparable in size with Jupiter. The remaining 4% of planets that are roughly similar in size with our planet are not only harder to find, but more valuable information-wise concerning that being smaller also make them harder, thus, more likely to be habitable. So far, 18 Earth-sized exoplanets have been identified.
Through a telescope that has new and more technological developed equipment, scientists have discovered 18 planets that are comparable in size with our planet, which were previously overlooked due to the difficulty of spotting them.
A new algorithm might help scientists to discover other Earth-sized exoplanets
Planets that are larger in size produce deep and clear brightness variations of the star their orbiting, fact that makes them easier to spot. However, the differences created by smaller planets are considerably challenging to differentiate from the natural brightness fluctuations of the star, which causes many telescopes to miss them while examining a different solar system.
Rene Heller from MPS managed to show that scientists could improve the sensitivity of the actual observation method, should they assume a more lifelike light curve in the algorithm that makes the search possible.
NASA researchers used data collected through the Kepler space telescope as a testing ground for their innovative algorithm. About 2300 planets were discovered between 2009 and 2013 subsequently to spotting the light curves of 100,000 stars. A technical issue forced scientists to use the telescope in a different observation mode, later dubbed as the K2 mission, through which 100,000 were monitored by 2018. Researchers agreed to once again analyze all 517 stars from K2 that were known to have at least one planet orbiting them.
Eighteen Earth-sized exoplanets were spotted so far
Additionally to the planets already monitored, researchers also identified 18 objects comparable in size with Earth, which have been previously missed. Most of them are proved to be too close their star to be habitable, but one of them showed similar conditions to our planet, being identified within the “habitable” zone.
Although this new algorithm, scientists state that there might be more planets which the telescope was not able to identify, especially considering that small planets that are further away from their stars are highly challenging to monitor.
However, this new method has incredible scientific potential, and scientists estimate that this method will allow them to discover over 100 other planets comparable in size to ours.