This artist’s impression reveals the planet K2-18b, its host star and an accompanying planet on this system. K2-18b is now the one super-Earth exoplanet identified to host each water and temperatures that would assist life. UCL researchers used archive information from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to research the starlight filtered via K2-18b’s ambiance. The outcomes revealed the molecular signature of water vapor, additionally indicating the presence of hydrogen and helium within the planet’s ambiance. Credit: ESA/Hubble, M. Kornmesser
An ambiance is a layer (or a number of layers) of gasoline that surrounds a planet, or different celestial physique.
If a celestial physique is surrounded by a layer, or a number of layers, of gasoline, then it’s mentioned to have an environment. Atmospheres are usually related to planets and stars, though different celestial our bodies can have them as properly, corresponding to comets, which have non permanent atmospheres. An ambiance might be acquired in numerous methods: it may be accreted onto a celestial physique by gravitational attraction, or it may be launched from a celestial physique itself in a course of known as outgassing. Whether or not a celestial physique retains its ambiance depends upon the physique’s mass and the temperature of the ambiance. Generally talking, the extra mass the physique has, and the cooler the ambiance, the higher probability it has of hanging onto its ambiance. For instance, a planet that’s in shut proximity to a star, and which subsequently receives loads of vitality, would possibly find yourself being stripped of its ambiance — as occurred to Mercury in our personal Solar System.
An ambiance is a layer (or a number of layers) of gasoline that surrounds a planet, or different celestial physique. Credit: NASA & ESA
While not one of its original science goals, Hubble has also made a name for itself as an explorer of exoplanets — planets orbiting stars outside the Solar System — in particular by studying their atmospheres. The chemical makeup of a planet’s atmosphere leaves a unique fingerprint on the starlight that passes through it. You can learn more about how Hubble studies the atmospheres of exoplanets in this video.
Hubble made the first detection ever of an organic molecule in the atmosphere of an exoplanet in 2008. Hubble found the tell-tale signature of the molecule methane in the atmosphere of the Jupiter-sized extrasolar planet HD 189733b. Under the right circumstances methane can play a key role in prebiotic chemistry — the chemical reactions considered necessary to form life as we know it. Although methane had been detected on most of the planets in our Solar System, this was the first detection of any organic molecule on a world orbiting another star. This breakthrough was an important step towards one day identifying signs of life on a planet outside our Solar System.
Credit: ESA/Hubble, M. Kornmesser
In 2016 Hubble analyzed for the first time the dry atmosphere of a super-Earth, 40 light-years away. Using Hubble’s data and new analysis techniques, the exoplanet 55 Cancri e was shown to have a dry atmosphere without any indication of water vapor. The discovery indicated that the atmosphere consists mainly of hydrogen and helium.
In 2019, in an exciting discovery, Hubble data were used to detect water vapor in the atmosphere of a super-Earth within the habitable zone. K2-18b is eight times the mass of Earth and at the time of its discovery was the only exoplanet known to have both water and temperatures that could support life.
In 2021, used archival datasets from the Hubble Space Telescope to reveal the first evidence for water vapor in the atmosphere of Jupiter’s moon Ganymede, the result of the thermal escape of water vapor from the moon’s icy surface.
