Earth-Like Planets Are Tasty Tidbits For Hungry Stars!


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. 바카라사이트

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.

51 Peg b was discovered by Dr. Michel Mayor and Dr. Didier Queloz of the Geneva Observatory in Switzerland, and the existence of such a roasting hot Jupiter surprised astronomers, who believed that Jupiter-like planets could only dwell in the cold, outer regions surrounding their stars–like Jupiter in our own Sun’s family.

Since the discovery of 51 Peg b, almost a generation ago, many other strange and unforeseen alien worlds have been spotted by surprised astronomers, as they orbit around stars that are very similar to our own.

Of Stars And Exoplanets

All stars are born when a very dense blob secreted deep within a cold and dark interstellar molecular cloud–composed of star-birthing gas and dust–collapses under the mighty weight of its own gravity. Many such dark, enormous, and amorphous clouds haunt our Milky Way Galaxy, floating around in spooky silence in the Space between stars.

Brilliant, young stars are surrounded by swirling protoplanetary accretion disks that whirl around them. Baby planets are born from these accretion disks–composed of nourishing fine dust particles and gas. The dust particles that dance around within the whirling disks are very sticky, and cling to one another, forming ever larger and larger objects–from pebble size, to boulder size, to mountain-size, to planet-size. The larger primordial planet-forming bodies that eventually form, termed planetesimals, ultimately collide with one another and merge to create major planets–the full-grown children of the stars that they circle.

Almost 2000 alien worlds have been spotted by planet-hunting astronomers circling distant stars beyond our Sun. Approximately 1790 exoplanets dwell in 1110 planetary systems that include about 460 systems sporting multiple planets–at least, as of May 13, 2014.

The ill-fated, but highly productive Kepler Space Telescope spotted a few thousand candidate alien worlds of which, perhaps, 11% could be false-positives.

Astronomers think that there are at least 100 billion planets inhabiting are starlit, barred-spiral Milky Way Galaxy, with at least one planet-child on average per sparkling stellar parent. Our Galaxy also possibly hosts trillions of rogue–alternatively termed orphan— exoplanets, that are not bound to any star at all, but wander around through interstellar Space bereft of a stellar family. Such unfortunate, lonely worlds were likely unceremoniously evicted from the families of their parent-stars, as a result of catastrophic gravitational interactions with sister planets.

 


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