51 Pegasi b

Documentary Films: The Search for Earth Like Planets

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• published: 01 Aug 2014
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Documentary Films: The Search for Earth Like Planets The first exoplanet to be observed circling a Sun-like star was an enormous roaster, spotted by two Swiss astronomers who made the historic discovery back in 1995. Since then, around 1800 exoplanets orbiting stars beyond our Sun have been detected, bringing with them a treasure trove of information describing many rich and strange alien worlds for astronomers to pour over. In May 2014, a team of astronomers at Vanderbilt University in Nashville, Tennessee, announced their bizarre discovery that some faraway Sun-like stars, inhabiting our Milky Way Galaxy, hungrily devour tasty Earth-like planets that circle them in searing-hot, close-in orbits. These "Earth-eaters," during their development, snack on large quantities of the rocky stuff from which "terrestrial"planets--like Mercury, Venus, Earth, and Mars--are composed. Trey Mack, a doctoral student in astronomy at Vanderbilt, created a model that estimates the effect this sort of sinister diet has on a parent star's chemical composition. Mack and colleagues have also used this model to study a distant duo of twin stars that both possess their own set of planetary offspring. The results of this study were published online May 7, 2014 in the Astrophysical Journal. After obtaining a high-resolution spectrum for a target star, astronomers can now actually spot the tattle-tale signature of this evil feast. "Trey has shown that we can actually model the chemical signature of a star in detail, element by element, and determine how that signature is changed by the ingestion of Earth-like planets. After obtaining a high-resolution spectrum for a given star, we can actually detect that signature in detail," noted Dr. Keivan Stassun in a May 16, 2014 Vanderbilt University Press Release. Dr. Stassum is a professor of astronomy at Vanderbilt. This new model will enable astronomers to better understand the process of planet formation--as well as helping them in their ongoing and dedicated hunt for Earth-like worlds dwelling beyond our Sun. Stars are enormous, seething, and searing-hot balls composed of more than 98 percent hydrogen and helium gas. All of the other elements that may exist in the glaring furnace of a star compose less than 2 percent of their mass. In astronomical jargon, all atomic elements heavier than hydrogen and helium are termed metals, and they have coined the term metallicity to define the ratio of the relative abundance of iron to hydrogen in a star's chemical composition. Over the past twenty years, astronomers have developed new strategies to help them detect exoplanets in great numbers--and there have been several recent studies that attempt to link stellar metallicity with planet formation. One study, conducted by scientists at Los Alamos National Laboratory in New Mexico, suggests that stars sporting high metallicity are more likely to give rise to planetary systems than stars that are less richly endowed with elements heavier than helium. A second study argues that hot Jupiter planets are seen primarily in close, fast orbits around high metallicity stellar parents, while smaller planets are most frequently observed in orbit around stars with a diverse range of metallicities. The first alien planet to be discovered in orbit around a distant Sun-like star was a hot Jupiter dubbed 51 Pegasi b--or 51 Peg b, for short. This sizzling distant world proved to be enormous, hugging its parent-star, 51 Pegasi, fast and close. In fact, 51 Peg b orbits its stellar parent at a distance of only 4,300,000 miles--which is only a small fraction of the distance separating Mercury, the innermost planet in our Solar System, from the Sun.