2023-07-25 13:45:51
Water is essential for life as we know it. However, it has long been unclear how the water got to Earth and whether the same processes that led to its current abundance could operate on rocky exoplanets (planets outside our solar system) like Earth. New clues to the answer to that question could be found in the PDS 70 solar system, located 370 light-years away. The star is surrounded by two wide rings or disks of gas and dust, one inside the other. The separation between the closest disk to the star and the most distant is about 8,000 million kilometers. Within that gap between the two disks, two gas giant planets have been detected.
The new measurements made by the MIRI (Mid-InfraRed Instrument) instrument of the James Webb Space Telescope have detected water vapor in the inner disk of the system, at distances of less than 160 million kilometers from the star, the region in which rocky planets like Earth could be forming. The distance is similar to the one that separates the Sun from the Earth (about 150 million kilometers).
“We have detected water in other disks, but not so close and in a system in which planets are currently forming,” explains Giulia Perotti, from the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, who leads the international research team. “We couldn’t do these kinds of measurements before Webb.”
The sun of that solar system, PDS 70, is a star of spectral type K, that is, orange and a little cooler than the Sun. It is very young; it is estimated to be only 5.4 million years old, very little compared to the approximately 4.6 billion years that the Sun is.
Artist’s impression of the star PDS 70 and the protoplanetary disk closest to it. (Image: NASA, ESA, CSA, J. Olmsted (STScI))
Astronomers have yet to detect planets forming within the inner disk of PDS 70. However, they have observed raw material, in the form of silicates, for the formation of rocky worlds. The detection of water vapor implies that, if rocky planets are forming there, as it seems, they will have water from the start.
The James Webb Space Telescope (JWST) is the result of an international collaboration led by NASA, ESA and CSA, respectively the US, European and Canadian space agencies.
The new study is titled “Water in the terrestrial planet-forming zone of the PDS 70 disk.” And it has been published in the academic journal Nature. (Source: NCYT from Amazings)
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