The James Webb Space Telescope shows the universe with impressive, unprecedented clarity.
What are the tasks of Webb?
In addition, Webb will gain the most complete picture yet of objects in the Milky Way, namely some of the 5,000 planets discovered in the galaxy.Astronomers use the precision of telescope light analysis to decipher the atmosphere surrounding some of these nearby worlds.The properties of their atmosphere will be the key to understanding how the exoplanet formed and whether it shows signs of life.
What is the problem?
Researchers at the Massachusetts Institute of Technology (MIT) have conducted a new study.for decoding light signals may not be good enough to accurately interpret the new telescope's data.In particular , opacity models —tools that model the interaction of light with matter based on its properties —may requiresignificant readjustments to match the accuracy of Webb's data.
If these models are not finalized, then the propertiesplanetary atmospheres, such as their temperature, pressure, and elemental composition, can differ by an order of magnitude. This means that scientists are fatally wrong in their calculations.
Webb telescope illustration, NASA
There is a scientifically significant difference between the 5% and 25% content of a compound such as water, which current models cannot The model NASA scientists use to decipher the spectral information does not match theThe accuracy and quality of the data obtained from the James Webb Space Telescope.As the scientists noted, the problem of opacity needs to be addressed."
What is opacity?
Opacity is a measure of how easily photons pass through a material.As you know, photons of certain wavelengths can pass directly through a material, be absorbed or reflected back.It all depends on whether they interactwhether they are with certain molecules inside the material and how this happens. Such interaction also depends ontemperature and pressure of the material.
The opacity model works based on various assumptions about how lightinteracts with matter. Astronomers use it to derive certain properties of the material, taking into account the spectrum of light emitted by the material. In the context of exoplanetsThe opacity model makes it possible to decipher the type and content of chemicals in a planet's atmosphere based on the light that is fromIt is reflected and captured by the telescope.
What's going on now?
The current modern model of opacity, which MIT has compared to a classic language translation tool, "worksIt normally deciphers spectral data from telescopes such as the Hubble Space Telescope.
First photo of JSWT, NASA
“So far, this Rosetta stone is all“okay,” the scientists write. But now that scientists are moving to the “next level,” working with Webb’s ultra-precise instruments, the current translation process “won’t capture the important subtleties.” For example, those that distinguish a planet suitable for life from an uninhabitable one.
What have the scientists done?
In a new study, MIT researchers looked forwhat atmospheric properties the model will receive if it is customized. The goal is to allow certain limitations in understanding how light and matter interact. As a result, scientists created eight such “perturbed” models.
They then stocked each model includingreal version, “synthetic spectra”. We are talking about patterns of light that scientists have modeled. They are similar to the accuracy that the James Webb telescope could record.
What did the scientists find out?
It turned out that, based on someand the same light spectra, each perturbed model provides large-scale predictions of the properties of the planet's atmosphere. Based on their analysis, the scientists concluded that if existing opacity models were applied to the light spectra captured by the Webb telescope, they would reach a certain “wall of accuracy.” In simple terms, they will not be sensitive enough to find out the real temperature of the planet (300 or 600 degrees Kelvin, 26.85 °C - 326.85 °C) and what gas occupies 5% or 25% of the atmospheric layer .
This difference is important so that scientists can constrain planet formation mechanisms and reliably identify biosignatures.
The team also found that each model alsoprovided a “good fit” to the data. This means that even if the perturbed model provided the wrong chemical composition, it generated its light spectrum. It was close enough to "correspond" to the original.
What's the bottom line?
There are enough parameters that need to be adjusted, even with the wrong model, to get a good fit. This means that you cannot know for sure that the model is incorrect.
Scientists have come up with several ideas about howimprove existing opacity models. For example, additional laboratory measurements and theoretical calculations need to be carried out to refine assumptions about how light and various molecules interact. Collaboration between scientists from different fields is also necessary. In particular, between astronomers and spectroscopy specialists.
Much could be done if we knew perfectly how light and matter interacted.
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Hi-Tech translated and adapted Jennifer's articleChu's "Study: Astronomers risk misinterpreting planetary signals in James Webb data," published in MIT News, a site covering news about MIT research, innovation, and teaching. The original article can be found at the link.
Cover illustration: Thibaut Roger, Thibaut Roger
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