nasa吧 关注:68,498贴子:206,407
  • 6回复贴,共1

韦伯望远镜发现了水蒸气,但是来自一个岩石行星还是它的恒星?

只看楼主收藏回复

Webb Finds Water Vapor, But From a Rocky Planet or Its Star?
韦伯望远镜发现了水蒸气,但是来自一个(系外)岩石行星还是它的恒星?
The most common stars in the universe are red dwarf stars, which means that rocky exoplanets are most likely to be found orbiting such a star. Red dwarf stars are cool, so a planet has to hug it in a tight orbit to stay warm enough to potentially host liquid water (meaning it lies in the habitable zone). Such stars are also active, particularly when they are young, releasing ultraviolet and X-ray radiation that could destroy planetary atmospheres. As a result, one important open question in astronomy is whether a rocky planet could maintain, or reestablish, an atmosphere in such a harsh environment.


IP属地:浙江1楼2023-05-02 11:30回复
    宇宙中,最普遍的恒星是红矮星,这也意味着系外岩石行星最可能被发现绕着这样的恒星旋转。


    IP属地:浙江2楼2023-05-02 11:33
    回复
      To help answer that question, astronomers used NASA’s James Webb Space Telescope to study a rocky exoplanet known as GJ 486 b. It is too close to its star to be within the habitable zone, with a surface temperature of about 800 degrees Fahrenheit (430 degrees Celsius). And yet, their observations using Webb’s Near-Infrared Spectrograph (NIRSpec) show hints of water vapor. 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. Water vapor has been seen on gaseous exoplanets before, but to date no atmosphere has been definitely detected around a rocky exoplanet. However, the team cautions that the water vapor could be on the star itself – specifically, in cool starspots – and not from the planet at all.


      IP属地:浙江3楼2023-05-02 11:34
      回复
        “We see a signal, and it’s almost certainly due to water. But we can't tell yet if that water is part of the planet's atmosphere, meaning the planet has an atmosphere, or if we’re just seeing a water signature coming from the star,” said Sarah Moran of the University of Arizona in Tucson, lead author of the study.


        IP属地:浙江4楼2023-05-02 11:35
        收起回复
          “Water vapor in an atmosphere on a hot rocky planet would represent a major breakthrough for exoplanet science. But we must 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, principal investigator on the program.


          IP属地:浙江5楼2023-05-02 11:35
          回复
            Webb Finds Water Vapor, But From a Rocky Planet or Its Star? | NASA
            https://www.nasa.gov/feature/goddard/2023/webb-finds-water-vapor-but-from-a-rocky-planet-or-its-star


            IP属地:浙江6楼2023-05-02 11:40
            回复