They warn that while this may be a sign of a planetary environment, the water might be on the star itself– particularly, in cool starspots– and not from the world at all.GJ 486 b is about 30% larger than the Earth and weighs three times as much. The science teams analysis reveals hints of water vapor; however, computer system designs show that the signal might be from a water-rich planetary atmosphere (suggested by the blue line) or from starspots from the red dwarf host star (suggested by the yellow line). The most common stars in the universe are red dwarf stars, which suggests that rocky exoplanets are most likely to be found orbiting such a star. If the water vapor is associated with the planet, that would indicate that it has an atmosphere despite its scorching temperature and close proximity to its star. While the water vapor might potentially suggest the presence of an atmosphere on GJ 486 b, an equally plausible description is water vapor from the star.
To help answer that question, astronomers utilized NASAs James Webb Space Telescope to study a rocky exoplanet referred to as GJ 486 b. It is too close to its star to be within the habitable zone, with a surface area temperature level of about 800 degrees Fahrenheit (430 degrees Celsius). And yet, their observations using Webbs Near-Infrared Spectrograph (NIRSpec) show hints of water vapor. That would suggest that it has an environment in spite of its scorching temperature level and close distance to its star if the water vapor is associated with the planet. Water vapor has actually been seen on gaseous exoplanets prior to, but to date no atmosphere has been definitively identified around a rocky exoplanet. The group warns that the water vapor could be on the star itself– particularly, in cool starspots– and not from the world at all.
” We see a signal and its probably due to water. We cant inform yet if that water is part of the planets atmosphere, meaning the planet has an atmosphere, or if were simply seeing a water signature coming from the star,” said Sarah Moran of the University of Arizona in Tucson, lead author of the research study.
” Water vapor in an environment on a hot rocky world would represent a major breakthrough for exoplanet science. We need to be careful and make sure that the star is not the culprit,” added Kevin Stevenson of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, primary detective on the program.
GJ 486 b has to do with 30% bigger than the Earth and 3 times as enormous, which means it is a rocky world with stronger gravity than Earth. It orbits a red dwarf star in simply under 1.5 Earth days. It is expected to be tidally locked, with a long-term day side and a permanent night side.
GJ 486 b transits its star, crossing in front of the star from our perspective. If it has an atmosphere, then when it transits starlight would filter through those gasses, inscribing fingerprints in the light that allow astronomers to translate its structure through a technique called transmission spectroscopy.
The results from all 3 are consistent in that they reveal a mostly flat spectrum with an appealing rise at the shortest infrared wavelengths. The team ran computer models thinking about a number of different particles, and concluded that the most likely source of the signal was water vapor.
While the water vapor might possibly suggest the existence of an atmosphere on GJ 486 b, an equally plausible description is water vapor from the star. Remarkably, even in our own Sun, water vapor can in some cases exist in sunspots since these areas are extremely cool compared to the surrounding surface area of the star. GJ 486 bs host star is much cooler than the Sun, so even more water vapor would focus within its starspots. As an outcome, it might create a signal that imitates a planetary environment.
” We didnt observe proof of the planet crossing any starspots during the transits. That does not imply that there arent areas elsewhere on the star. And thats exactly the physical circumstance that would imprint this water signal into the information and might end up looking like a planetary environment,” explained Ryan MacDonald of the University of Michigan in Ann Arbor, among the research studys co-authors.
A water vapor atmosphere would be expected to gradually wear down due to outstanding heating and irradiation. As an outcome, if an atmosphere exists, it would likely need to be constantly renewed by volcanoes ejecting steam from the worlds interior. If the water is certainly in the worlds atmosphere, extra observations are required to narrow down how much water exists.
If the planet has no atmosphere, or just a thin environment, then the hottest part of the day side is expected to be straight under the star. If the hottest point is shifted, that would suggest an environment that can flow heat.
Ultimately, observations at shorter infrared wavelengths by another Webb instrument, the Near-Infrared Imager and Slitless Spectrograph (NIRISS), will be needed to separate in between the planetary environment and starspot circumstances.
” Its signing up with multiple instruments together that will actually select whether or not this planet has an environment,” stated Stevenson.
The research study is accepted for publication in The Astrophysical Journal Letters.
The James Webb Space Telescope is the worlds premier area science observatory. Webb will solve secrets in our planetary system, look beyond to far-off worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
By observing GJ 486 b transit in front of its star, astronomers looked for signs of an atmosphere. They warn that while this may be an indication of a planetary atmosphere, the water could be on the star itself– particularly, in cool starspots– and not from the world at all.GJ 486 b is about 30% bigger than the Earth and weighs three times as much.
If exoplanet GJ 486 b has an environment, more observations will be required to figure out.
GJ 486 b is about 30% bigger than the Earth and three times as massive, which indicates it is a rocky world with stronger gravity than Earth. It orbits a red dwarf star in just under 1.5 Earth days. It is too close to its star to be within the habitable zone, with a surface temperature of about 800 degrees Fahrenheit. And yet, Webb observations show tips of water vapor.
The water vapor could be from an environment covering the planet, in which case it would need to be continuously renewed due to losses from outstanding irradiation. But an equally most likely possibility is that the water vapor is really from the external layer of the planets cool host star. Additional Webb observations will assist answer the question: Can a rocky planet preserve, or reestablish, an environment in the harsh environment near a red dwarf star?
This graphic reveals the transmission spectrum acquired by Webb observations of rocky exoplanet GJ 486 b. The science groups analysis reveals hints of water vapor; nevertheless, computer system designs show that the signal could be from a water-rich planetary environment (shown by the blue line) or from starspots from the red dwarf host star (suggested by the yellow line). The 2 models diverge noticeably at shorter infrared wavelengths, suggesting that additional observations with other Webb instruments will be required to constrain the source of the water signal.Credit: NASA, ESA, CSA, Joseph Olmsted (STScI), Sarah E. Moran (University of Arizona), Kevin B. Stevenson (APL), Ryan MacDonald (University of Michigan), Jacob A. Lustig-Yaeger (APL).
Webb Space Telescope Finds Water Vapor, But From a Rocky Planet or Its Star?
The most common stars in the universe are red dwarf stars, which indicates that rocky exoplanets are most likely to be found orbiting such a star. Red dwarf stars are cool, so a world has to hug it in a tight orbit to remain warm sufficient to potentially host liquid water (implying it lies in the habitable zone).
