Astronomers using the space telescope “Hubble” found in the Earth’s atmosphere ozone is considered to be biosignatures using the moon reflecting off the sunlight. Scientists have carried out measurements during a lunar Eclipse and thus simulate the situation of observation of the transit of earth-like exoplanet over the disk of its star, allowing to improve the methodology of the study of atmospheres of other planets. Article published in the journal The Astronomical Journal.
As the number of discovered extrasolar planets grows, astronomers are increasingly interested not search for new objects, and full-scale study is already known, in particular their atmospheres. In the case of earth-like exoplanets requires a reliable methodology of search of biosignature their atmospheres with transit spectroscopy and direct observations. On the Earth one of the most important biosignature is oxygen, which is formed by oxygenic photosynthesis. Ozone, as a product of photolysis of oxygen is regarded as biosignature also the ozone layer acts as a screen that protects life on Earth from ultraviolet radiation from the Sun.
A team of astronomers headed by Allison Youngblood (Youngblood Allison) from the Laboratory for atmospheric and space physics in Colorado published results of unusual observations by a space telescope “Hubble”. The researchers tested the ability to detect ozone in the Earth’s atmosphere, which acted as a model exoplanet during its transit of the Sun. For this purpose the telescope during a full lunar Eclipse, on 20-21 January 2019 continuously recorded reflected from the surface of the moon the light of the Sun, passing through earth’s atmosphere, obtaining a transmission spectrum with spectrograph STIS.