Astronomers have revealed that they have detected an atmosphere around the super-Earth GJ 1132b marking the first time that an atmosphere was detected around an Earth-like planet besides our home planet.
Super-Earth GJ 1132b
The planet circles the very low mass-star GJ 1132 about 39 light-years away at the Southern constellation Vela. Researchers conducted a simultaneous observation of the planet at seven different wavelength bands ranging from the near-infrared and the optical using the GROND imaging instrument of the 2.2 m ESO/MPG telescope.
The amount of starlight lost when a planet passes in front of the host star allows astronomers to estimate the planet's size. In the case of GJ 1132b, researchers found that the exoplanet was only 1.4 times as big as the Earth when they measured the decrease in the brightness of the starlight as the planet and its atmosphere absorbed and blocked some of the starlight during transit.
They also found that the planet is larger in one of the wavelength bands, which suggests it has an atmosphere that is opaque to a specific light but transparent to others.
John Southworth, from Keele University who led the team that made the discovery, said that their findings is a significant step to detecting life outside the Solar System.
Scientists currently use a method that analyzes the chemical composition of a planet's atmosphere to find life on extraterrestrial worlds. Chemical imbalances could mean the presence of living organisms. The large amounts of oxygen on Earth are a tell-tale sign of life on our home planet.
Prior to the newly announced discovery, the only detection of atmosphere on planets outside of our star system involved gas giants.
"The planet is significantly hotter and a bit larger than Earth," Southworth said. "One possibility is that it is a "water world" with an atmosphere of hot steam."
Very Low-Mass Stars
The planet's host star is a very low-mass star, which makes the discovery of the atmosphere encouraging because these types of stars are very common and are known to host many small planets.
Very low-mass stars are also characterized by a lot of magnetic activity, which causes the production of high levels of ultraviolet light and X-rays that can completely evaporate the atmospheres of the planets.
Hunt For Life Outside Solar System
The properties of GJ 1132b, however, show it has an atmosphere that can endure this condition for billions of years sans getting destroyed. Given that very low-mass stars and planets are common in the universe, conditions suitable for life could be common.
Researchers said that Hubble Space Telescope and ground-based facilities can help confirm their findings.
"Detecting the atmospheres of low-mass low-temperature exoplanets is a high-priority goal on the path to ultimately detect biosignatures in the atmospheres of habitable exoplanets," the researchers wrote in their study published in the Astronomical Journal.
"New observations with HST and existing ground-based facilities would be able to confirm the present detection and further constrain the atmospheric composition of the planet."
