This exoplanet is the first alien world that was confirmed by observations made by the James Webb Space Telescope.
For the first time, researchers confirmed an exoplanet—a planet orbiting another star—using the James Webb Space Telescope. Formally classified as LHS 475 b, the alien world is located 41 light-years away, in the constellation Octans, and is almost exactly the same size as Earth. In fact, as per researchers, this not-so-distant exoplanet is 99% the diameter of our world. Led by Kevin Stevenson and Jacob Lustig-Yaeger, both from the Johns Hopkins University Applied Physics Laboratory in Laurel, the research team chose to carefully review the targets of interest for the Transiting Exoplanet Survey Satellite (TESS), which hinted at the existence of the planet in question. Webb’s Near Infrared Spectrograph (NIRSpec) was able to quickly and clearly identify and confirm the exoplanet’s existence with just two transit observations. “There is no doubt that the planet is there. Webb’s pristine data validates this,” said Lustig-Yaeger.
A distant alien world similar to Earth
What is impressive beyond the observations by Webb is that this exoplanet is believed to be a rocky word. Whatmore, Webb’s observations of a distant alien world similar in diameter to Earth open many possibilities that will allow scientists to study and research the atmospheres of exoplanets with the state-of-the-art space telescope. Although we have lots of ground-based telescopes and a few operating in space, only Webb is capable of accurately characterizing the atmosphere of Earth-sized planets. Despite this, and although astronomers have already begun to study the atmosphere of the alien world by looking at its transmission spectrum, they have still been unable to determine the atmosphere or say whether it has one.
LHS 475 b: What’s there and what’s not
The James Webb Space Telescope is very sensible. It can easily detect a variety of molecules, but nonetheless, researchers explain they have still not been able to come to conclusions about the atmosphere of the alien world. And while scientists at this time can’t say what is present in the atmosphere of LHS 475 b, they can say what is not there. The astronomers explained that this exoplanet could not have a thick methane-dominated atmosphere similar to that of Saturn’s moon Titan. Scientists also note that while there is a possibility that the planet has no atmosphere, some atmospheric compositions have not been ruled out, such as an atmosphere of pure carbon dioxide. To figure out if this alien world has an atmosphere and what this could be like, follow-up observations have already been reserved for the summer of 2023, when scientists will turn the space telescope towards the alien world in hopes of learning more about it.
What we know and what we don’t
And while some may say the data provided by Webb is not enough, scientists have learned a lot about this exoplanet. For example, James Webb’s data has helped them understand that this world is a few hundred degrees warmer than our planet. If they detect clouds, it can lead experts to conclude that this world resembles planets like Venus. If this is the case, scientists can also conclude the world has an atmosphere dominated by carbon dioxide and is likely perpetually engulfed with thick layers of clouds. The new observations also have been able to tell us more about its orbit. LHS 475 b completes an orbit around its star in just two days. This data was obtained thanks to Webb’s precise light curve measurement. Although LHS 475 b is closer to its star than any other planet in our solar system, its star, a red dwarf star, is less than half the temperature of the Sun. This means that although LHS 475 b orbits its star in extremely close proximity, it could still have an atmosphere.