Monday, April 10, 2023

3952 - EXOPLANET DISCOVERIES - more planets

 

-   3952 -   EXOPLANET  DISCOVERIES  -  more planets.   An Earth-size exoplanet spotted just 72 light-years away.  Researchers hope to discover more exoplanets in this K2-415 system.


------------  3952  -  EXOPLANET  DISCOVERIES  -  more planets

-    K2-415b, as the newly discovered world has been named, orbits the nearby red dwarf star K2-415. Researchers identified the exoplanet in the data of NASA's now-defunct Kepler space telescope, its secondary mission K2, and its successor, the Transiting Exoplanet Survey Satellite.

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-     While K2-415b is not the closest known exoplanet to Earth, it is, on a cosmic scale, one of our close neighbors.  The K2-415 system is unique in that K2-415 is one of the coolest, or lowest-mass, stars known to host an exoplanet.  There are only four stars cooler than K2-415 that are known to host at least one exoplanet, including the famous TRAPPIST-1, which has seven known exoplanets.

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-    One motivation for investigating the planets around such low-mass stars is to understand and clarify whether those planets form and evolve just like the planets around solar-type stars.

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-    Solar-type stars are stars akin to our sun. Red dwarf stars (also known as M-dwarfs), on the other hand, are far cooler and much smaller. K2-415 is thought to have a surface temperature of about 5,250 degrees Fahrenheit, compared to our sun's 9,900 degrees F, with a diameter of 0.2 solar radii and a mass just 0.16 times that of the sun.

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-    K2-415b is not in the habitable zone of its star, or the distance from a star at which liquid water can exist on a world's surface. The exoplanet is extremely close to K2-415, so close that it only takes about four Earth days to complete an orbit.

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-   But,  there is a possibility that there is another planet lurking in the system that sits inside the habitable zone.   Astronomers will study K2-415b further, determining its mass and internal structure. Preliminary estimates peg the exoplanet as about three times more massive than Earth, despite having a radius just 1.015 times that of Earth.

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-   So far, only one transiting planet was found in the system, but this does not  necessarily mean the system is a 'single' one.  Further radial velocity observations, as well as photometric monitoring, will be able to constrain the presence of outer planets in this system.

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-   James Webb Space Telescope finds a 'hot Jupiter' exoplanet that defies expectations.  The exoplanet “Smertrios” has a surprising abundance of heavy elements in its atmosphere.

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-   The atmospheres of gas giant planets across the Milky Way galaxy can be very different from those in our solar system, the James Webb Space Telescope has found.  Observations of the distant exoplanet HD149026b, also known as Smertrios, revealed that the planet's atmosphere is rich in what scientists call heavy elements, essentially anything other than hydrogen and helium. In Smertrios' atmosphere, they detected high concentrations of carbon and oxygen.

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-    The results have taken astronomers by surprise. In gas giant planets of our solar system, such as Jupiter, Saturn, Uranus and Neptune, scientists see a clear correlation between the planet's mass and the amount of heavy elements in the atmosphere. The more massive the planet, the lower the concentrations of these elements in its atmosphere.

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-    The giant planets of our solar system exhibit a nearly perfect correlation between both overall composition and atmospheric composition and mass.

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-   Astronomers have seen more diverse atmospheric compositions in gas giant exoplanets previously, but the composition of the atmosphere of HD149026b is off the charts.   The planet is the mass of Saturn, but its atmosphere seems to have as much as 27 times the amount of heavy elements relative to its hydrogen and helium that we find in Saturn.

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-   HD149026b, or Smertrios, is a Jupiter-like planet that orbits extremely close to its parent star. In the case of Smertrios, this distance is so short that the planet's year lasts only three Earth days. As a result of this close proximity to the star, temperatures in Smertrios' atmosphere reach a scorching 2,700 degrees Fahrenheit, which is three times higher than the surface temperature of the solar system's hottest planet, Venus.

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-    It appears that every giant planet is different, and we're starting to see those differences thanks to JWST.   The research has determined how many molecules there are relative to the primary component of the gas, which is hydrogen, the most common element in the universe. That tells us quite a lot about how this planet formed.

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-    By measuring the atmospheric composition of a planet, scientists can get an insight into the chemistry of its parent star and the material from which it formed millions or billions of years ago.

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-   The planetary disk that gave rise to Smertrios must have had much more carbon compared to oxygen than the disk that birthed our solar system. The origin of this diversity is a fundamental mystery in our understanding of planet formation.

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-   Further atmospheric observations of extrasolar planets with JWST will quantify this diversity better and yield constraints on more complex trends that might exist. We have shown definitively that the atmospheric compositions of giant extrasolar planets do not follow the same trend that is so clear in the solar system planets.

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                   April 9, 2023        EXOPLANET  DISCOVERIES  -  more planets         3952                                                                                                                          

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--------------------- ---  Monday, April 10, 2023  ---------------------------

 

 

 

 

           

 

 

 

 

 

           

 

 

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