Space
Hubble Space Telescope Discovers 'Polluted' Dead Stars and Signs of Earth-like Planets
Catherine Griffin
First Posted: May 09, 2013 02:41 PM EDT
NASA's Hubble Space Telescope has made an unusual find. It's discovered signs of Earth-like planets among dead, polluted stars in a nearby star cluster. The pollution itself may be caused by debris from asteroid-like objects falling onto the stars.
Known as white dwarfs, these dim remnants of "dead" stars were once very much like the Sun. Located about 150 light years away in the Hyades star cluster, the two stars possess silicon in their atmospheres--a major ingredient of the rocky material that forms Earth and other terrestrial planets in the Solar system.
In fact, white dwarfs are prime targets when looking for Earth-like planets. Although astronomers believe that all stars form in clusters, hunts for planets in these clusters have not been fruitful; of the roughly 800 exoplanets that have been discovered, only four are known to orbit stars in clusters. This could be due to the nature of cluster stars, which are young and active and make it difficult to observe exoplanets. Yet this also means that older, "retired" stars are better places to search for these planets.
The two white dwarfs are encircled by rocky debris, which whirl around the dead stars. In fact, it's possible that when these stars were born, terrestrial planets formed around them. Yet after the stars collapsed to form white dwarfs, the surviving gas giant planets may have gravitationally nudged members of any leftover asteroid belts into the star-grazing orbits. This may explain the current belt of debris.
"We have identified chemical evidence for the building blocks of rocky planets," said Jay Farihi of the University of Cambridge in a news release. "When these stars were born, they built planets, and there's a good chance that they currently retain some of them. The signs of rocky debris we are seeing are evidence of this--it is at least as rocky as the most primitive terrestrial bodies in our Solar System."
What is more interesting is the fact that researchers actually detected low levels of carbon in the stars' atmosphere. It could be another sign that points to the rocky nature of the debris orbiting the white dwarfs.
"The one thing the white dwarf pollution technique gives us that we won't get with any other planet detection technique is the chemistry of solid planets," said Farihi in a news release.
In fact, after examining the amount of silicon and carbon present, the researchers were able to determine that the rocky material was basically Earth-like. Now, the researchers are expanding their hunt. They plan to analyze more white dwarfs using the same technique in order to identify the rocks' composition and their parent bodies.
The findings are published in the Monthly Notices of the Royal Astronomical Society.
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First Posted: May 09, 2013 02:41 PM EDT
NASA's Hubble Space Telescope has made an unusual find. It's discovered signs of Earth-like planets among dead, polluted stars in a nearby star cluster. The pollution itself may be caused by debris from asteroid-like objects falling onto the stars.
Known as white dwarfs, these dim remnants of "dead" stars were once very much like the Sun. Located about 150 light years away in the Hyades star cluster, the two stars possess silicon in their atmospheres--a major ingredient of the rocky material that forms Earth and other terrestrial planets in the Solar system.
In fact, white dwarfs are prime targets when looking for Earth-like planets. Although astronomers believe that all stars form in clusters, hunts for planets in these clusters have not been fruitful; of the roughly 800 exoplanets that have been discovered, only four are known to orbit stars in clusters. This could be due to the nature of cluster stars, which are young and active and make it difficult to observe exoplanets. Yet this also means that older, "retired" stars are better places to search for these planets.
The two white dwarfs are encircled by rocky debris, which whirl around the dead stars. In fact, it's possible that when these stars were born, terrestrial planets formed around them. Yet after the stars collapsed to form white dwarfs, the surviving gas giant planets may have gravitationally nudged members of any leftover asteroid belts into the star-grazing orbits. This may explain the current belt of debris.
"We have identified chemical evidence for the building blocks of rocky planets," said Jay Farihi of the University of Cambridge in a news release. "When these stars were born, they built planets, and there's a good chance that they currently retain some of them. The signs of rocky debris we are seeing are evidence of this--it is at least as rocky as the most primitive terrestrial bodies in our Solar System."
What is more interesting is the fact that researchers actually detected low levels of carbon in the stars' atmosphere. It could be another sign that points to the rocky nature of the debris orbiting the white dwarfs.
"The one thing the white dwarf pollution technique gives us that we won't get with any other planet detection technique is the chemistry of solid planets," said Farihi in a news release.
In fact, after examining the amount of silicon and carbon present, the researchers were able to determine that the rocky material was basically Earth-like. Now, the researchers are expanding their hunt. They plan to analyze more white dwarfs using the same technique in order to identify the rocks' composition and their parent bodies.
The findings are published in the Monthly Notices of the Royal Astronomical Society.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone