To find out what extrasolar planets are made of, astronomers analyze the way in which their atmospheres absorb starlight of different colors and compare it to a model, or ‘spectrum,’ to identify different molecules, including those of methane – an indicator of potential life.
“Current models of methane are incomplete, leading to a severe underestimation of methane levels on planets,” explained Prof Jonathan Tennyson, a scientist with University College London and a co-author of a paper published in the Proceedings of the National Academy of Sciences.
Prof Tennyson and his colleagues developed a new spectrum for ‘hot’ methane which can be used to detect the molecule at temperatures above that of Earth, up to 1,500 K (1,220 degrees Celsius).
“The comprehensive spectrum we have created has only been possible with the astonishing power of modern supercomputers which are needed for the billions of lines required for the modeling,” said lead author Dr Sergei Yurchenko, also from University College London.
“We limited the temperature threshold to 1,500K to fit the capacity available, so more research could be done to expand the model to higher temperatures still,” he said.
“Our calculations required about 3 million CPU hours alone; processing power only accessible to us through the DiRAC project.”
“We are thrilled to have used this technology to significantly advance beyond previous models available for researchers studying potential life on astronomical objects, and we are eager to see what our new spectrum helps them discover.”
The tool has been tested and verified by successfully reproducing in detail the way in which the methane in failed stars, called brown dwarfs, absorbs light.
“We anticipate our new model will have a big impact on the future study of planets and ‘cool’ stars external to our Solar System, potentially helping scientists identify signs of extraterrestrial life,” Prof Tennyson concluded.
Spectrum of hot methane in astronomical objects using a comprehensive computed line list, Published at PNAS on July, 2014