Planet WASP-39 b has water vapor, carbon dioxide, and sulfur dioxide, but nothing to suggest it could harbor life


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The James Webb Space Telescope, in flight since Christmas Day 2021, is already doing top-notch science. Its image transmission provides so much information and of such quality that astronomers, astrophysicists and even astrobiologists refer to it as a before and after. Whether this assessment is real or exaggerated, what is certain is that an exoplanet, a planet outside our solar system, has never been seen with such high resolution until now. The space telescope has focused on the planet WASP-39 b, located about 700 light years from Earth. The images give information of atoms, molecules and even signals of chemical activity and clouds. The journal Science publishes this week a wide collection of articles on all these questions.


The widget, equipped with the most sophisticated technology used to date, has been made possible thanks to the collaboration of NASA, ESA and the Canadian Space Agency. The main milestone achieved, according to a press release released by NASA, has been to define the molecular and chemical profile of a distant planet for the first time. WASP-39 b has been defined by the members of the mission as a "hot Saturn", a planet "almost as massive" as Saturn but with a smaller orbit than that of Mercury around a star similar to our Sun, all just 10% smaller. His day is equivalent to only four Earth days, the same length of time as his year. Apparently, it is a gas planet, and the proximity to the star means that the temperature on its surface easily reaches 1,000 degrees Celsius.



A "spectacular" find


Ignasi Ribas, director of the Institut d'Estudis Espacials de Catalunya (IEEC) and internationally recognized expert in the study of exoplanets, defines the mission of the James Webb telescope and the data it has reported as "spectacular". The telescope, he says, uses a technique called "transmission spectrometry", which allows to detect how much light passes through the atmosphere when the planet passes in front of the star and, depending on the measurement, to identify the chemical compounds that have interacted with this light "Given the high resolution of the instruments, the interpretation of the data can be fine-tuned", he explains. Water vapour, carbon dioxide and sulfur dioxide have been found there, all very abundant. "The surprises have been finding sulfur dioxide in such abundance and the absence of methane", he adds. The cause, most likely,



Although the data published so far is "preliminary", Ribas believes that the science that can be developed is, again, "spectacular". "The uncertainties in the measurements are of the order of 10 times lower than any other telescope".


Observations so far confirm the presence of water vapor and carbon dioxide, which suggests that part of future research will focus on developing more sophisticated computer models that include parameters such as photochemistry and the influence of the star's radiation, heat circulation or a more realistic and detailed structure of the atmosphere. And for the next stages, focus the telescope towards colder, rocky and smaller planets than WASP-39 b. "There are already candidates", reflects Ribas: among the nearly 5,000 known exoplanets, those "few dozen" that minimally resemble Earth's conditions.



Is there life on WASP-39 b?


The physical conditions already known before the exoplanet WASP-39 b made us think that it would be difficult to find life there. A gas giant like this, with temperatures close to 1,000 degrees Celsius and a distance to its star 20 times less than that of Mercury to the Sun, does not give many options, regardless of the composition of its atmosphere. Another thing is that there are traces of life, as Jordi Urmeneta, microbiologist and expert in microbial ecology at the University of Barcelona, ​​calls them. "It is not an obvious candidate to harbor life", he confirms.


"More than what has been seen, it is necessary to talk about the possibility of examining the atmosphere of exoplanets", he continues. Urmeneta emphasizes that the James Webb telescope opens the door to examine planets that are within the habitable zone, that is, rocky, with the possibility of liquid water and at a "convenient" distance from their star. As long as no physical samples can be taken, he insists, the only option is to analyze the composition of the atmosphere taking into account the predictions of the ecologist James Lovelock, author of the Gaia theory: "Life drastically modifies its environment ”, and in a very special way the atmosphere. "We are very far from the primordial chemical balance". Life contributes to it, he assures.


According to Urmeneta, it is necessary to look for life where there are conditions and a structure close to those of Earth. If you find an atmosphere far from chemical equilibrium, the doors open to talk about the possibility of life. "Earth's primordial atmosphere was very similar to that of Venus or Mars, basically of carbon dioxide - he says -. Life has changed him."


In the TRAPPIST system, located 39 light-years away in the constellation Aquarius, there are at least three planets located in the habitable zone and, therefore, with conditions to have life there. Europa, a moon of Jupiter, would also have some of these conditions. Compared to extreme environments on Earth itself, there are microorganisms known to live at very high or very low temperatures, or without oxygen or in environments normally considered hostile, a field of research that also helps to know what and where must search