NASA web search for atmospheres around habitable extrasolar planets, This month marks the third anniversary of the discovery of an extraordinary system of seven planets called TRAPPIST-1.
Seven rocky and earth-sized worlds orbit stars that are very cold 39 light-years from Earth. Three of these planets are in the habitable zone, which means they are in the right orbit so that it is warm enough to have liquid water on its surface.
When launched in 2021, NASA’s James Webb space telescope will monitor these worlds to conduct the first detailed, near-infrared study of the atmosphere in the planet’s habitable zone. now the NASA web search for atmospheres around habitable extrasolar planets.
To find signs of the atmosphere, astronomers will use a technique called spectroscopic transmission. You watch the parent star as the planet crosses the surface of a star known as a transit. Starlight filters the planet’s atmosphere, which absorbs some starlight and leaves fingerprints in the star’s spectrum.
The atmosphere for finding extrasolar planets – the word scientists use for planets outside our solar system – will not be easy. Their atmosphere is more compact than gas giants, while due to their smaller size, they capture less than starlight.
TRAPPIST-1 is one of the best targets available for Webb because the star itself is also quite small, which means that the size of the planets is bigger relative to the star.
The atmosphere is more difficult to recognize, but the prize is higher. It would be very interesting to make the first discovery of a planet the size of Earth. NASA web search for atmospheres around habitable extrasolar planets.
Red dwarfs like TRAPPIST-1 tend to have terrible eruptions that can make the planet TRAPPIST-1 unfriendly. Determining whether they have an atmosphere, and if so, what they are made of, is the next step in determining whether life as we know it can survive in this distant world.
More than one team of astronomers will study the TRAPPIST-1 system using Webb.
They plan to use various tools and monitoring modes to establish as much detail as possible for each planet in the system.
The Laffrener program targets TRAPPIST-1d and -1f to not only find the atmosphere but also determine its core composition.
They hope to distinguish between an atmosphere dominated by water vapor or an atmosphere consisting mostly of nitrogen (like Earth) or carbon dioxide (like Mars and Venus).
The Lewis program will monitor TRAPPIST-1e for similar purposes. TRAPPIST-1e is one of the planets outside our solar system that has similarities with the Earth in terms of its density and the amount of radiation it receives from its star.
This makes it a good candidate for resolution – but scientists need to know more to understand it.
In particular, astronomers continue to argue that gas planets are very close to their stars. Most believe that such planets must continue to form in protoplanetary discs – discs around the star where the planet was born – because more material is available from the star and then migrates inward.
However, other scientists assume that even large gas giants can form relatively close to their stars.
To inform the debate, astronomers will study the carbon-oxygen ratio in the selection of extrasolar planets. This ratio can be used to track where the planet was formed because it varies with distance from stars.
In addition to studying planets using transmission spectroscopy, the team will also use a technique called phase curves. This involves observing planets in all their orbits, which is only practical for the hottest world with the shortest orbits.
A planet orbiting its star is very closely regulated, which means that it always shows that star with the same face as the Earth’s moon.
As a result, distant observers observing planets see through different phases because different sides of the planet are seen at different points in their orbits. By measuring planets at different times, astronomers can map atmospheric temperatures as a function of length.
This technique was introduced by NASA’s Spitzer Space Telescope, which created the first extrasolar planetary time map in 2007.
Astronomers can also model the vertical structure of the atmosphere by observing the planet’s own heat emissions.