![]() ![]() This artist’s concept shows what the sub-Neptune exoplanet TOI-421 b might look like. But there’s a conspicuous absence – a “size gap” – of planets that fall between 1.5 to 2 times the size of Earth (or in between super-Earths and sub-Neptunes) that scientists have been working to better understand. In the middle lie rocky super-Earths and larger sub-Neptunes with puffy atmospheres. The Exoplanet Size GapĮxoplanets (planets outside our solar system) come in a variety of sizes, from small, rocky planets to colossal gas giants. In a new study using NASA’s retired Kepler Space Telescope, astronomers find evidence of a possible cause: The cores of these planets are pushing away their atmospheres from the inside out. Some exoplanets seem to be losing their atmospheres and shrinking. This discovery helps explain the observed size gap in exoplanets and indicates a significant atmospheric loss process different from the previously theorized photoevaporation.Ī new study could explain the ‘missing’ exoplanets between super-Earths and sub-Neptunes. False Positive Probabilities For All Kepler Objects Of Interest: 1284 Newly Validated Planets And 428 Likely False Positives. The Astrophysical Journal, Volume 822, Number 2 (2016) DOI:10.Researchers using data from the Kepler Space Telescope have found that some exoplanets are shrinking due to loss of their atmospheres, likely caused by radiation from their cores. We have so much exoplanet data and so many exoplanet candidates that we can’t keep up. It’s a dramatic change from just two decades ago when only a handful of exoplanets were known. Now that exoplanets number in the thousands, we have to shift our methods away from sorting through data by hand and rely on statistical algorithms. ![]() ![]() This method allows us to narrow down the amount of exoplanet data. However the exact number isn’t important. Given the odds, it is likely that about 100 of these new exoplanets will later be outed as false positives. So it’s a bit misleading to say that exactly 1,284 new exoplanets have been confirmed. Some of these had previously been confirmed by other means, but 1,284 have not been confirmed previously. They found that about 2,000 of them had less than 1% odds of being a false positive. They had the program analyze data from more than 7,000 “objects of interest” in the Kepler data, which at first glance look like planetary transits. Rather than pouring over data by hand, a team of astronomers wrote a program to determine the odds of an exoplanet being a false positive, based on a comparison to known false positives. But Kepler has observed nearly 150,000 main sequence stars, and there it simply isn’t practical to go through all of that data by hand.Įnter statistical analysis. It takes careful analysis to distinguish a real planet from a poser, and it isn’t something that can be done quickly by hand. There have been instances where a planet was added to the list of confirmed exoplanets and then later removed upon further analysis. So there is always the potential of getting a false positive. Stars have some natural variation in brightness due to things like solar flares, and starspots moving across the surface of a star can look quite similar to a transiting planet. In principle the process is straight forward, but in practice it can be extremely difficult. ![]()
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