This follows from the model calculations that reproduce the measured variation in brightness of the starlight reprocessed by the planet. The new observations with MIRI (Mid-Infrared Instrument) on board JWST for the first time also prove that the atmosphere beyond hydrogen and helium must have a high fraction of heavy elements. Organic compounds are currently the hottest candidates. Intensive research is being carried out in various laboratories to determine which substances these could be. Similar to how the ozone layer on Earth reacts with the Sun’s UV radiation, analogous processes could also be responsible for the production of the chemical compounds of the haze found in the upper atmosphere of GJ 1214 b and perhaps many Mini-Neptunes. In observing GJ 1214 b, astronomers tracked the planet’s signal as a function of the degree of illumination, obtaining data of the entire planet. Similar to how we see Venus in the solar system, such a planet shows different fractions of its day and night sides, the phases, during an orbit. This image illustrates how a star illuminates and heats the day side of a tidally locked planet orbiting in bound rotation. Presumably, the atmosphere of the primordial Earth also consisted partly of tholins. The term “tholin”, coined by Carl Sagan, describes a variable mixture of hydrocarbons found on Saturn’s moon Titan and other bodies in the Solar System. “Neither soot particles nor so-called tholins reflect the star’s radiation sufficiently strongly,” Steinrueck states. At least, the usual candidates have been ruled out. ![]() Exactly what this layer consists of, however, remains a mystery, as none of the compositions suspected so far provides a satisfactory explanation. ![]() The data can only be explained by the researchers’ assumption of a layer in the planet’s upper atmosphere that reflects the radiation from the central star, which GJ 1214 b orbits once in 38 hours, unusually well. ![]() She is a co-author of the paper, which appears in the journal Nature, and performed the model calculations essential for evaluating the observations. “Our results show that the haze layer of GJ 1214 b must have a composition different from known celestial bodies,” says Maria Steinrueck from the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. The results indicate an unusually highly reflective, dense haze in the upper atmosphere and show evidence of water vapour and methane. To this end, astronomers have now measured the infrared radiation of the planet classified as a Mini-Neptune with the MIRI spectrograph of the James Webb Space Telescope (JWST) and evaluated it with the help of model calculations. Hurt (IPAC)Īfter almost 15 years of futile efforts, an international team of researchers involving the Max Planck Institute for Astronomy has determined some of the atmosphere’s properties of the exoplanet GJ 1214 b. ![]() The planet probably has large amounts of water. An unusually reflective haze layer in the upper atmosphere makes it difficult to determine the composition of the sheets below. GJ 1214 b is a warm Mini-Neptune with a perpetual day on one side and eternal night on the other. Artist’s impression of the exoplanet GJ 1214 b, based on the current results.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |