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Tiny planet epic fetus5/18/2023 René Heller's team has now been able to show that the sensitivity of the transit method can be significantly improved, if a more realistic light curve is assumed in the search algorithm. Their effect on the stellar brightness is so small that it is extremely hard to distinguish from the natural brightness fluctuations of the star and from the noise that necessarily comes with any kind of observation. Small planets, however, present scientists with immense challenges. Large planets tend to produce deep and clear brightness variations of their host stars so that the subtle center-to-limb brightness variation on the star hardly plays a role in their discovery. The maximum dimming of the star occurs in the center of the transit just before the star becomes gradually brighter again," he explains. When a planet moves in front of a star, it therefore initially blocks less starlight than at the mid-time of the transit. "In reality, however, a stellar disk appears slightly darker at the edge than in the center. Rene Heller from MPS, first author of the current publications. "Standard search algorithms attempt to identify sudden drops in brightness," explains Dr. If a star happens to have a planet whose orbital plane is aligned with the line of sight from Earth, the planet occults a small fraction of the stellar light as it passes in front of the star once per orbit. In their search for distant worlds, scientists often use the so-called transit method to look for stars with periodically recurring drops in brightness. Common search algorithms were not sensitive enough. And they have another thing in common: all 18 planets could not be detected in the data from the Kepler Space Telescope so far. The smallest of them is only 69 percent of the size of the Earth the largest is barely more than twice the Earth's radius. The 18 newly discovered worlds fall into the category of Earth-sized planets. Moreover, small worlds are fascinating targets in the search for Earth-like, potentially habitable planets outside the solar system. This percentage likely does not reflect the real conditions in space, however, since small planets are much harder to track down than big ones. Of these so-called exoplanets, about 96 percent are significantly larger than our Earth, most of them more comparable with the dimensions of the gas giants Neptune or Jupiter. Somewhat more than 4000 planets orbiting stars outside our solar system are known so far.
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