Its size and surface gravity are much larger than Earth's, and its radiation environment may be hostile, but a distant planet called K2-18b has captured the interest of scientists all over the world. For the first time, researchers have detected water vapor signatures in the atmosphere of a planet beyond our solar system that resides in the "habitable zone," the region around a star in which liquid water could potentially pool on the surface of a rocky planet.
Astronomers at the Center for Space Exochemistry Data at the University College London in the United Kingdom used data from NASA's Hubble Space Telescope to find water vapor in the atmosphere of K2-18b, an exoplanet around a small red dwarf star about 110 light-years away in the constellation Leo.
This artist's impression shows the planet K2-18b, its host star and an accompanying planet in this system. K2-18b is now the only super-Earth exoplanet known to host both water and temperatures that could support life. UCL researchers used archive data from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to analyze the starlight filtered through K2-18b's atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet's atmosphere.
Credit: ESA/Hubble, M. Kornmesser
If confirmed by further studies, this will be the only exoplanet known to have both water in its atmosphere and temperatures that could sustain liquid water on a rocky surface. Liquid water would only be possible if the planet turns out to be terrestrial in nature, rather than resembling a small version of Neptune.
Given the high level of activity of its red dwarf star, K2-18b may be more hostile to life as we know it than Earth, as it is likely to be exposed to more high-energy radiation.
The planet, discovered by NASA's Kepler Space Telescope in 2015, also has a mass eight times greater than Earth's. That means the surface gravity on this planet would be significantly higher than on our planet.
The team used archive data from 2016 and 2017 captured by Hubble and developed open-source algorithms to analyze the host star's light filtered through K2-18b's atmosphere. The results revealed the molecular signature of water vapor, and also suggest the presence of hydrogen and helium in the planet's atmosphere.
The authors of the paper, published in Nature Astronomy, believe that other molecules, including nitrogen and methane, may be present but they remain undetectable with current observations.
Further studies are required to estimate cloud coverage and the percentage of atmospheric water present. A paper from a different team of scientists using Hubble observations has been submitted to the Astronomical Journal.
K2-18b is one of hundreds of "super-Earths" -- exoplanets with masses between those of Earth and Neptune -- found by Kepler. NASA's TESS mission is expected to detect hundreds more super-Earths in the coming years.
The next generation of space telescopes, including the James Webb Space Telescope, will be able to characterize exoplanet atmospheres in more detail.
The Hubble Space Telescope is a project of international cooperation between ESA (the European Space Agency) and NASA.
Claire Andreoli | EurekAlert!
Black hole at the center of our galaxy appears to be getting hungrier
12.09.2019 | University of California - Los Angeles
Milestones on the Way to the Nuclear Clock
12.09.2019 | Technische Universität Wien
Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.
If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...
Researchers from Chalmers University of Technology have demonstrated a detector made from graphene that could revolutionize the sensors used in next-generation space telescopes. The findings were recently published in the scientific journal Nature Astronomy.
Beyond superconductors, there are few materials that can fulfill the requirements needed for making ultra-sensitive and fast terahertz (THz) detectors for...
A supersolid is a state of matter that can be described in simplified terms as being solid and liquid at the same time. In recent years, extensive efforts have been devoted to the detection of this exotic quantum matter. A research team led by Tilman Pfau and Tim Langen at the 5th Institute of Physics of the University of Stuttgart has succeeded in proving experimentally that the long-sought supersolid state of matter exists. The researchers report their results in Nature magazine.
In our everyday lives, we are familiar with matter existing in three different states: solid, liquid, or gas. However, if matter is cooled down to extremely...
A team headed by Prof. Steve Albrecht from the HZB will present a new world-record tandem solar cell at EU PVSEC, the world's largest international photovoltaic and solar energy conference and exhibition, in Marseille, France on September 11, 2019. This tandem solar cell combines the semiconducting materials perovskite and CIGS and achieves a certified efficiency of 23.26 per cent. One reason for this success lies in the cell’s intermediate layer of organic molecules: they self-organise to cover even rough semiconductor surfaces. Two patents have been filed for these layers.
Perovskite-based solar cells have experienced an incredibly rapid increase in efficiency over the last ten years. The combination of perovskites with classical...
Researchers from the University of Pennsylvania provide a molecular map of every cell in a developing animal embryo
In a paper in Science this week, Penn researchers report the first detailed molecular characterization of how every cell changes during animal embryonic...
10.09.2019 | Event News
04.09.2019 | Event News
29.08.2019 | Event News
12.09.2019 | Physics and Astronomy
12.09.2019 | Materials Sciences
12.09.2019 | Trade Fair News