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In April 2018, NASA launched the Transiting Exoplanet Survey Satellite (TESS). Its primary goal is to locate Earth-sized planets and larger "super-Earths" orbiting nearby stars for further study. One of the most powerful tools that will examine the atmospheres of some planets discovered by TESS will be NASA's James Webb Space Telescope. Since observing small exoplanets with thin atmospheres like the Earth will be difficult for Webb, astronomers will first target the Gaseous Gaseous Exoplanets easier.
Some of Webb's early observations of gaseous exoplanets will be made as part of the Director's Discretionary Early Release Science program. The exoplanets project team in transit at the center of Webb's scientific operations plans to perform three types of observations that will provide new scientific knowledge and a better understanding of the performance of Webb's scientific instruments.
"We have two main objectives. is to transfer webb exoplanets datasets as quickly as possible to the astronomical community and to do great science so that astronomers and the public can see how powerful this observatory is, "said Jacob Bean of the University of Chicago. co-principal investigator on the project of exoplanets in transit.
"Our team aims to provide critical knowledge and knowledge to the astronomical community that will help catalyze exoplanet research and use Webb on time. added Natalie Batalha of NASA Ames Research Center, principal investigator of the project.
Transit-An Atmospheric Spectrum
When a planet passes, or transits, its host star, the light of the Star is filtered through the atmosphere of the planet.Molecules present in the atmosphere absorb certain wavelengths or colors of light.By dividing starlight In a rainbow spectrum, astronomers can detect sections of missing light and determine which molecules are in the atmosphere of the planet.
For these observations, the project team selected WASP -79b.780 light years from Earth.The team expects to detect and measure the abundance of water, carbon monoxide and carbon dioxide in WASP- 79b Webb could also detect new molecules not yet seen in the atmospheres exoplanets
Phase Curve-A Weather Map
Planets whose orbits are very close to their stars tend to lock in tide. One side of the planet is permanently facing the star while the other side is facing, just as one side of the moon is still facing the earth. When the planet is in front of the star, we see its back cooler. But as it orbits around the star, more and more of the heat of the day appears. By observing an entire orbit, astronomers can observe these variations (called a phase curve) and use the data to map the temperature, clouds, and chemistry of the planet as a function of longitude.
The team will observe a warm Jupiter phase curve "known as WASP-43b, which orbits around its star in less than 20 hours." Looking at different wavelengths of light, they can sample the atmosphere at different depths and get a more complete picture of its structure. "We have already seen dramatic and unexpected variations for this planet with Hubble and Spitzer. With Webb, we will reveal these variations with much more details to understand the physical processes that are responsible, "said Bean.
Eclipse-In the Glow of the Planet
The biggest challenge when we observe an exoplanet is that the light of the star is much brighter, submerging the dim light of the planet.To circumvent this problem, one method is to observe a planet in transit when it disappears behind the star, and no when she crosses the star. By comparing the two measures, one taken when the star and the planet are visible, and the other when only the star is in view, astronomers can calculate the amount of light coming from of the planet alone.
planets shining brightly in infrared light. The team plans to study WASP-18b, a planet that is fired at a temperature of nearly 4800 degrees Fahrenheit (2,900 K). Among other questions, they hope to determine if the planet's stratosphere exists because of the presence of titanium oxide, vanadium oxide or another molecule.
Living Planets
Finally, astronomers want to use Webb to study potentially habitable planets. In particular, Webb will target planets in orbit around red dwarf stars, as these stars are smaller and lighter, making it easier to detect the signal of a planet in orbit. Red dwarfs are also the most common stars in our galaxy.
"TESS is expected to locate more than a dozen orbiting planets in habitable red dwarf areas, some of which may actually be habitable We want to know if these planets have Atmospheres and Webb will be the only one to tell us "said Kevin Stevenson of the Space Telescope Science Institute, a co-principal investigator on the project. "The results will go a long way towards answering the question of whether life-friendly conditions are common in our galaxy."
Learn more:
Hubble observes the exoplanet atmosphere in more detail than ever before
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