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The James Webb Space Telescope is like the part of the century that continues to be postponed. Due to its complexity and some abnormal readings that were detected during vibration testing, the launch date of this telescope has been postponed several times – it should be launched in 2021. But for obvious reasons, NASA remains committed
Once deployed, the JWST will be the most powerful space telescope in operation, and its advanced instrument suite will reveal things about the Universe that have never been seen before. Among these are the atmospheres of extra-solar planets, which will initially consist of gas giants. In doing so, the JWST will refine the search for habitable planets and eventually examine some potential candidates
The JWST will do this in conjunction with the Transiting Exoplanet Survey Satellite (TESS), which was deployed in space in April . As its name indicates, TESS will search for planets using the Transit (aka Transit Photometry) method, where stars are monitored for periodic dips of brightness – which are caused by a planet pbading in front of them relative to the planet. Observer
Artist concept of the Transiting Exoplanet Satellite Survey and its 4 telescopes. Credit: NASA / MIT
Some of Webb's early observations will be conducted through the director's Discretionary Early Release Science program – an exoplanet planet team in transit at Webb's scientific operations center. This team plans to conduct three types of observations that will provide new scientific knowledge and a better understanding of Webb's scientific instruments.
Jacob Bean of the University of Chicago, a co-principal investigator on the project of exoplanets in transit, explained: in a NASA press release:
"We have two goals The first is to transfer Webb's exoplanet datasets to the astronomical community as soon as possible.The second is to do a great science so that astronomers and the public can see how powerful this observatory is. . "
Natalie Batalha of NASA Ames Research Center, lead researcher of the project, added:
providing critical knowledge and ideas to the astronomical community that will help catalyze exoplanet research and make the most of of Webb in the limited time we have. "
For their first observation, the JWST be responsible for characterizing the atmosphere of a planet by examining the light that pbades through it. a planet pbades a star, and the way light is absorbed at different wavelengths provides clues as to the chemical composition of the atmosphere Unfortunately, existing space telescopes do not have not had the resolution necessary to scan anything else than a gaseous giant. 
The JWST with its advanced infrared instruments, will examine the light pbading in the exoplanet atmospheres , dividing it into a rainbow spectrum, and then deducing the composition of the atmospheres according to the sections of light that are missing.For these observations, the project team chose WASP-79b, an exoplanet the size of Jupiter who orbits a star d in the constellation Eridanus, about 780 light years from Earth.
The team expects to detect and measure WASP-79b abundances, but also hopes to find molecules that have not yet been detected in exoplanet atmospheres. For their second observation, the team will monitor a "hot Jupiter" known as WASP-43b, a planet that orbits its star with a period of less than 20 hours
Like all the exoplanets that gravitate around their stars, the gaseous giant is locked – where one side always faces the star. When the planet is in front of the star, astronomers can only see its colder back; but as it orbits, the warm side of the day slowly appears. By observing this planet for the whole of its orbit, astronomers will be able to observe these variations (called phase curves) and use the data to map the temperature, clouds and atmospheric chemistry of the planet.
These data will allow them to sample the atmosphere at different depths and obtain a more complete picture of the internal structure of the planet. As stated by Bean:
"We have already seen dramatic and unexpected variations for this planet with Hubble and Spitzer, and with Webb we will reveal these variations with much more detail to understand the responsible physical processes."
An exoplanet of about ten times the mbad of Jupiter located some 330 light-years away from Earth. Radiograph: NASA / CXC / SAO / I.Pillitteri et al .; Optics: DSS; Illustration: NASA / CXC / M.Weiss
For their third observation, the team will attempt to directly observe a planet in transit. It's very difficult, since the star's light is much brighter and therefore darkens the dim light reflected by the atmosphere of the planet. One method to remedy this is to measure the light coming from a star when it is visible, and again when it disappears behind the star.
By comparing the two measures, astronomers can calculate the amount of light coming from the planet alone. This technique works best for very hot planets that shine in infrared light, which is why they chose WASP-18b for this observation – a hot Jupiter that reaches temperatures of about 2900 K (2627 ° C). ). In the process, they hope to determine the composition of the stifling stratosphere of the planet.
In the end, these observations will help test the JWST's capabilities and calibrate its instruments. The ultimate goal will be to examine potentially habitable exoplanet atmospheres, which in this case will include rocky (or "telluric") planets that orbit around low-mbad red dwarf stars. In addition to being the most common star in our galaxy, red dwarfs are also considered the most likely place to find telluric planets.
NASA's James Webb telescope, shown here the artist's design, will provide more information on previously detected exoplanets. Beyond 2020, many more next-generation space telescopes should rely on what he discovers. Credit: NASA
As explained Kevin Stevenson, researcher at the Space Telescope Science Institute and co-principal investigator on the project:
"TESS is expected to locate more than a dozen orbiting planets in the habitable areas of the red dwarfs, some of which might be really habitable.We want to know if these planets have atmospheres and Webb will be the only one to tell us.The results will answer the question of whether the conditions favorable to the life is common in our galaxy. "
The James Webb Space Telescope will be the world's first space science observatory once deployed, will help astronomers solve mysteries in our solar system, study exoplanets, and observe the earliest periods of the Universe to determine how its large-scale structure has evolved over time.For this reason, it is understandable that NASA is asking the astronomical community to be patient until they are sure that it will unfold successfully.
When the reward will be nothing but revolutionary discoveries, it is just to wait. In the meantime, be sure to watch this video on how scientists are studying the atmospheres of the exoplanets, courtesy of the Space Telescope Science Institute:
NASA
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Matt Williams is the Curator of the Universe The Space Guide Today. He is also an independent writer, science fiction writer and Taekwon-Do instructor. He lives with his family on Vancouver Island, in beautiful British Columbia.
exoplanets, starring, James Webb Space Telescope, jwst, TESS, transit method, exoplanet transit survey satellite
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