(ORDO NEWS) — American researchers have come to the conclusion that nitric oxide (I), or laughing gas, in the atmosphere of exoplanets can act as a marker of the presence of life.
These data will be taken into account when the James Webb Space Telescope acquires information about the atmospheres of rocky exoplanets resembling Earth.
Scientists from the University of California at Riverside (USA) suggested that the typical list of chemicals used by astrobiologists to search for life on other planets is missing nitric oxide (I), or laughing gas (N 2 O).
The list of chemical compounds in the planet’s atmosphere that can indicate the presence of life usually includes gases that are abundant in the Earth’s atmosphere today. However, laughing gas has always received very little attention.
Now researchers have estimated how much nitrous oxide living things can produce on a terrestrial planet.
They then created computer models of such a planet orbiting various types of stars and determined the amount of N 2 O that an observatory like the James Webb Space Telescope could detect.
As an example, the authors of the work considered the star system TRAPPIST-1, located in the constellation Aquarius and well suited for studying rocky planets in the star’s habitable zone.
The scientists concluded that nitrous oxide could potentially be detected in TRAPPIST-1 at levels comparable to carbon dioxide or methane.
In the Earth’s atmosphere, N 2 O appears as a result of the vital activity of various bacteria, but this is not the only way. The authors took this into account during the simulation.
A small amount of nitrous oxide is created, for example, by lightning.
However, along with N 2 O, lightning also produces nitrogen dioxide, which can help astrobiologists distinguish between weather conditions and the biological processes that created this gas.
In addition, it was believed that N 2 O would be difficult to detect at a great distance.
But this conclusion is based on today’s N 2 O concentrations in the Earth’s atmosphere: it does not take into account periods in the history of our planet when conditions favored much greater biological release of N 2 O.
The authors also reported that the radiation from stars of spectral classes K and M (the latter includes the star TRAPPIST-1) destroys N 2 O molecules much less efficiently than the Sun.
The combination of these two effects can significantly increase the concentration of N 2 O in the atmospheres of potentially habitable planets.
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