New research from astronomers at the University of Washington uses the exciting TRAPPIST-1 planetary system as a kind of laboratory to model not the planets themselves, but how the upcoming James Webb space telescope can detect and study their atmospheres, on their way to look for life beyond the earth.
The study, led by Jacob Lustig-Yaeger, a UW doctoral student in astronomy, finds that the James Webb telescope, started in 2021, could perhaps learn key information about the atmosphere in the TRAPPIST-1 worlds even during its first year of operation unless – as an old song goes – clouds get in the way.
"The web telescope has been built, and we have some idea how it will work," Lustig-Yaeger said. "We used computer modeling to determine the most efficient way to use the telescope to answer the most basic question we want to ask, which is: Are there even atmospheres on these planets, or not?"
His paper, "The Discoverability and Characterization of TRAPPIST-1 Exoplanet Atmospheres with JWST," was published online in June in the Astronomical Journal .
TRAPPIST-1 system, 39 light years – or about 235 trillion miles – The departure of the constellation Aquarius interests astronomers because of its seven orbiting rocky or earth-like planets. Three of these worlds are in the star's habitable zone – the stretch of space around a star that is just right to allow liquid water on the surface of a rocky planet, thereby giving life a chance.
The star, TRAPPIST-1, was much warmer when formed than it is now, which would have exposed all seven planets to ocean, ice and atmospheric loss earlier.
"There is a big question in the field right now about whether these planets even have atmospheres, especially the innermost planets," Lustig-Yaeger said. "Once we have confirmed that there are atmospheres, what can we learn about every atmosphere of the planet – the molecules that make up it? "
Given how he suggests that the James Webb Space Telescope can search, it can learn a lot in a short space of time finds this paper.
Astronomers detect exoplanets as they pass in front of or "transports" its host star, resulting in a measurable dimming of starlight. Planets approach their star transport more often and it's easier to study. When a planet transmits its star, some of the star's light passes through the planet's atmosphere, which astronomers can learn about the molecular composition of the atmosphere.
Lustig-Yaeger said that astronomers can see small differences in the size of the planet when they look in different colors, electricity smiles at wavelengths, on light.
"This happens because the gases in the planet's atmosphere absorb light only in very specific colors. Since each gas has a unique "spectral fingerprint," we can identify them and begin to assemble the composition of the exoplanet's atmosphere. "
Lustig-Yaeger said that the team's modeling indicates that the James Webb telescope, which uses a versatile onboard tool called the Near-Infrared Spectrograph, could detect the atmosphere of all seven TRAPPIST-1 planets in 10 or fewer transits – if they have And of course we don't know if they have clouds or not.
If the TRAPPIST-1 planets have thick, globally orbiting clouds like Venus does, atmospheric detection can take up to 30 transits.
"But it is still an achievable goal, "he said." That means that even in the case of realistic high altitude clouds, the James Webb telescope will still be able to detect the presence of atmospheres – as before our paper was unknown. "
exoplanets have been discovered recently, but astronomers have not yet discovered their atmospheres. The modeling in this study, said Lustig-Yaeger, "shows that this TRAPPIST-1 system is detecting Earth's orbit dna exoplanet atmospheres on the horizon with the James Webb Space Telescope – perhaps well within its primary five-year mission. " . This can leave cases where abiotically produced oxygen – not representative of life – fills an exoplanet atmosphere, which can provide a kind of "false positive" for life. If this is the case with TRAPPIST-1 planets, the Web telescope may also be able to detect them.
Lustig-Yaeger's co-author, both with UW, is Astronomy Professor Victoria Meadows, who is also the lead investigator for the UW-based virtual planetary laboratory; and astronomer PhD student Andrew Lincowski. The work partly follows on earlier works by Lincowski, which models possible climates for the seven TRAPPIST-1 worlds.
"In doing this study we have looked at: What are the best case scenarios for the James Webb Space Telescope" What will it be able to do? Because there will definitely be more Earth sizes found before they were launched in 2021. "
The research was funded by a grant from the NASA Astrobiology Program's Virtual Planetary Laboratory team, as part of the Nexus for Exoplanet System Science (NExSS) research coordination network.
Lustig-Yaeger added: "It's hard to imagine the theory of a planetary system better suited to James Webb than TRAPPIST-1."
The study provides new climate models of the small star TRAPPIST 1's seven exciting worlds
Jacob Lustig-Yaeger et al. The discoverability and characterization of TRAPPIST-1 Exoplanet Atmospheres with JWST, The Astronomical Journal (2019). DOI: 10.3847 / 1538-3881 / ab21e0
James Webb Space Telescope could start learning about TRAPPIST-1 atmospheres in a single year, the study shows (2019, August 14)
retrieved August 14, 2019
This document is subject to copyright. In addition to all fair dealings for private studies or research, no
part may be reproduced without written permission. The content is provided for informational purposes only.