Scientists found 18 Earth-sized Exoplanets in Space

Scientists found 18 Earth-sized Exoplanets in Space

Scientists found 18 Earth-sized Exoplanets in Space
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Researchers used a new algorithm to draw a more realistic image of the exoplanet population in order to locate Earth-sized exoplanets.

Humanity has discovered around 4,000 planets outside our solar system until now and most of them are considerably larger than Earth. According to an estimate, nearly 96% of these exoplanets are comparable with the likes of Jupiter and Neptune. Having said that, the real distribution of exoplanets is quite different from this pattern. Scientists believe that there are numerous Earth-sized exoplanets in space but observing them is extremely difficult, in comparison to their larger companions.

Transit Method

The most common method to search distant worlds is to observe the brightness of their host stars. If the orbital plane of an exoplanet is aligned with the line of sight from Earth, a slight dimming of the star is observed while the planet is passing its host. Dr. Rene Heller, the Lead Author of the study who is a Researcher at the Max Planck Institute for Solar System Research, explained the transit method in the following words:

Standard search algorithms attempt to identify sudden drops in brightness. In reality, however, a stellar disk appears slightly darker at the edge than in the center. When a planet moves in front of a star, it therefore initially blocks less starlight than at the mid-time of the transit. The maximum dimming of the star occurs in the center of the transit just before the star becomes gradually brighter again.

He also mentioned that the 18 newly-discovered Earth-sized exoplanets were not detected by traditional algorithms because they were not sensitive enough to extract the information about such small bodies from the dataset of the Kepler Space Telescope.

New Algorithm for Earth-sized Exoplanets

Heller explained that the effect of large planets on the brightness variations of their host stars is quite clear, which makes it comparatively easy to identify. Contrary to that, the changes in the stellar brightness due to small planets is so minimal that it becomes incredibly hard to distinguish it from natural fluctuations. In order to overcome this problem, researchers came up with a more realistic light curve to improve the overall sensitivity of the transit method (new algorithm). Michael Hippke, a member of the researching team from Sonneberg Observatory, provided the best possible summary of the process by saying,

Our new algorithm helps to draw a more realistic picture of the exoplanet population in space. This method constitutes a significant step forward, especially in the search for Earth-like planets.

Sample Data for the New Algorithm

In order to test the efficiency of the new algorithm, the researching team analyzed all the 517 planet-harboring stars that were identified during the K2 mission of the Kepler Space Telescope. The results revealed 18 new, Earth-sized exoplanets that were missing in previous investigations. Most of these new planets have temperatures in excess of 100o C and some of them even heat up to 1000o C. Similarly, the orbits of these exoplanets are closer to their previously-known companions. Kai Rodenbeck, a Co-author of the study from the University of Gottingen, referred to the similarity between these Earth-sized exoplanets as he said,

“In most of the planetary systems that we studied, the new planets are the smallest.”

Odd One Out

Researchers found that one of these exoplanets is different from the rest as it lies in the habitable zone of its host star. They believe that it may have liquid water on its surface, given the ideal location. Despite the amazing achievement, the team of Heller acknowledged that their method might have missed some exoplanets. Basically, small planets at large distances are the most problematic ones because they need more time to complete their orbit around the central stars. Therefore, detecting the transit of such planets is significantly harder to detect.

100 Earth-sized Exoplanets

The success of their algorithm has motivated the researching team to make more amazing discoveries and they are planning to trace 100 more Earth-sized exoplanets from the data of the Kepler mission. This method will also give a massive boost to the PLATO mission, which is scheduled to be launched in 2026 by the European Space Agency. You can get some useful insights about this revolutionary mission here

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