Aug. 13, 2009 -- Vaporized remains of rock and lava circle a very young star, creating a ring of debris scientists believe formed after a violent crash of two planetary bodies. The host star is HD 172555, located about 100 light-years away in the southern constellation Pavo, or Peacock. Scientists using NASA's infrared-sensitive Spitzer Space Telescope found unexpected chemical signatures when they analyzed the star's light. Lead researcher Carey Lisse, with Johns Hopkins University Applied Physics Laboratory in Laurel, Md., recognized the fingerprints of melted glass and gases such as silicon monoxide -- created by vaporized rock -- that he had seen from the comet-smashing Deep Impact and the comet-sampler Stardust missions. "Without those two missions we wouldn't have had the confidence to say what it is we were seeing. Now we're aware of what's possible," Lisse told Discovery News. "This was something that really stood out hard." Scientists suspect an object about the size of Earth's moon crashed into a Mercury-sized body orbiting HD 172555 about 1,000 years ago, creating an unusual debris ring circling about as far as the distance of Jupiter from the sun. A similar event early in the history of our solar system is believed to have positioned material for Earth's moon to form. The crash around HD 172555, however, likely booted debris too far from its fledgling planet's gravitational grasp to coalesce into a moon. Related Content:
"The impact that formed (Earth's) moon had to happen relatively slow," Lisse said. "It's much easier to see a big, spread-out mass." The scientists' research appears in next week's Astrophysical Journal. It follows a report this week of another potential cosmic collision that turned around a planet's orbit. WASP-17, which orbits a star about 1,000 light-years from Earth, is the first planet ever found that circles its mother star in the opposite direction from how the star spins. WASP is the acronym for the Wide Area Search for Planets, run by a consortium of U.K.-based universities. So far, the most likely explanation for the backward orbit is that the planet's path was reversed very early in its history as a result of an impact or near-miss with another body. "It's one that the theorists need to do a lot of investigation on," astronomer Coel Hellier, of Keele University, told Discovery News. "All the (computer) models that would result in having a retrograde (backward) orbit, you need some other body that is perturbing it." Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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