Astronomers using NASA's Hubble Space Telescope have gone looking for water vapour in the atmospheres of three planets orbiting stars similar to the sun — and have come up nearly dry.
The three planets, HD 189733b, HD 209458b, and WASP-12b, are between 60 and 900 light-years away. These giant gaseous worlds are so hot, with temperatures between 1,500 and 4,000 degrees Fahrenheit, that they are ideal candidates for detecting water vapour in their atmospheres. However, to the surprise of the researchers, the planets surveyed have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories.
So, there is need of revision of the already established theories so far.All the math done in predicting the tabulation of water sources and atmosphere has been question marked relatively with the unfamiliar observation made by the Hubble telescope.
"Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside the solar system, and we can now say with much greater certainty than ever before that we've found water in an exoplanet," said Nikku Madhusudhan of the Institute of Astronomy at the University of Cambridge, England, who led the research. "However, the low water abundance we are finding is quite astonishing."The planets were selected because they orbit relatively bright stars that provide enough radiation for an infrared-light spectrum to be taken. Absorption features from the water vapor in the planet's atmosphere are superimposed on the small amount of starlight that glances through the planet's atmosphere.
The three planets, HD 189733b, HD 209458b, and WASP-12b, are between 60 and 900 light-years away. These giant gaseous worlds are so hot, with temperatures between 1,500 and 4,000 degrees Fahrenheit, that they are ideal candidates for detecting water vapour in their atmospheres. However, to the surprise of the researchers, the planets surveyed have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories.
So, there is need of revision of the already established theories so far.All the math done in predicting the tabulation of water sources and atmosphere has been question marked relatively with the unfamiliar observation made by the Hubble telescope.
"Our water measurement in one of the planets, HD 209458b, is the highest-precision measurement of any chemical compound in a planet outside the solar system, and we can now say with much greater certainty than ever before that we've found water in an exoplanet," said Nikku Madhusudhan of the Institute of Astronomy at the University of Cambridge, England, who led the research. "However, the low water abundance we are finding is quite astonishing."The planets were selected because they orbit relatively bright stars that provide enough radiation for an infrared-light spectrum to be taken. Absorption features from the water vapor in the planet's atmosphere are superimposed on the small amount of starlight that glances through the planet's atmosphere.
The findings were published on July 24, 2014 in The Astrophysical Journal Letters. The study included researchers from the Space Telescope Science Institute (STScI), the University of Maryland, Johns Hopkins University and the University of Toronto.