April 14, 2021 The chemical fingerprint of exoplanet HD 209458b’s atmosphere reveals as many as 6 molecules and that it has migrated inwards from its birthplace much farther out in its star system. Artist’s concept of exoplanet Osiris – aka HD 209458b – as it transits in front of its star. Note the illuminated crescent of the planet, where the colors illustrate the light spectra that – like a chemical fingerprint – let astronomers identify as many as 6 molecules in the planet’s atmosphere. “It’s the first time so many molecules have been measured and points to an atmosphere with more carbon than oxygen”, they said. Image via University of Warwick/ Mark Garlick.