Is there life on other planets? This remains one of astronomy’s biggest questions. In order to determine whether an exoplanet could be hospitable to life as we know it, we first need to take a peek into its atmosphere and find out what sort of elements it harbors.
The way we can do that from a vast distance is with the help of giant space telescopes, such as the James Webb Space Telescope that NASA plans to launch in 2021, as reported by the Inquisitr.
The space agency has already fired off into space its newest planet-hunting spacecraft, the Transiting Exoplanet Survey Satellite (TESS). Launched on April 16 with the goal of seeking out transiting exoplanets (spotted as they pass in front of their parent star), the spacecraft will be zeroing in on Earth-sized exoplanets and “super-Earths,” the Inquisitr reported at the time.
Once these exoplanets are located by the TESS satellite, the James Webb Space Telescope will swoop in to do some investigating and look into their atmospheric composition to assess their potential of being habitable, NASA announced yesterday.
“TESS should locate more than a dozen planets orbiting in the habitable zones of red dwarfs, a few of which might actually be habitable. We want to learn whether those planets have atmospheres and Webb will be the one to tell us,” said Webb co-principal investigator Kevin Stevenson at the Space Telescope Science Institute.
To pull it off, Webb will be engaging beforehand in three types of scientific observations on three different exoplanets aimed at testing out the telescope’s brand-new instruments and gathering as much data as possible.
“Since observing small exoplanets with thin atmospheres like Earth will be challenging for Webb, astronomers will target easier, gas giant exoplanets first,” space agency officials stated in a news release.
Looking At Absorbed Wavelengths On WASP-79b
Studying an exoplanet’s atmospheric spectrum, or the wavelengths that survive as starlight is absorbed by the planet’s atmosphere, can provide a clear picture of what type of molecules can be found in it. This is because each element absorbs a different wavelength of the host star’s light as it passes through the atmosphere of the transiting planet.
In the video below, NASA explains how the James Webb Space Telescope will study the atmosphere of distant exoplanets with the help of transmission spectroscopy — a method that analyzes the light wavelengths absorbed and filtered out by a transiting planet to see which corresponding elements are present in its atmosphere.
According to NASA, Webb will be testing out its transmission spectroscopy on an exoplanet called WASP-79b, a gas giant the size of Jupiter found 780 light-years from Earth. The telescope will be peering through WASP-79b’s atmosphere to measure its water, carbon monoxide, and carbon dioxide content.
Checking Out Phase Curves On WASP-43b
A phase curve describes the variations in brightness of tidally-locked exoplanets as they complete a full orbit and more of their hot day-side becomes visible to our telescopes.
Since tidally-locked planets only expose to us their dark side, the bright side being permanently oriented toward their parent star, the best way to find out more about their atmosphere is to examine their phase curves.
Cue exoplanet WASP-43b, a “hot Jupiter” 261 light-years away which orbits its host star in less than 20 hours. Previously imaged with the Hubble and the Spitzer space telescopes, this exoplanet will also be checked out by Webb to see the different wavelengths of starlight that pass through its atmosphere at different depths and get a clearer picture of its structure.
Measuring The Glow Of WASP-18b
While some planets can be particularly bright (for instance Venus, the brightest planet in our solar system), the light coming from a planet is considerably fainter than that of its eclipsing parent star.
But there’s a way to see just how bright very hot exoplanets really are, and that’s measuring their glow before and after they transit their host star.
To perform these measurements for the very first time, Webb will be setting its eyes on a famous exoplanet known as WASP-18b, which the telescope plans to observe both when it passes in front of its star and when it sneaks behind it.
Located 325 light-years from Earth, this “hot Jupiter” has been dubbed the “death planet” because it is shrouded in a toxic stratosphere with no water but tons of carbon monoxide, the Inquisitr reported a while back.
One of Webb’s tasks is to find out “whether the planet’s stratosphere exists due to the presence of titanium oxide, vanadium oxide, or some other molecule,” explained NASA.