Sunday, April 2, 2023

3943 - EXOPLANETS - Earth size with atmospheres?

 

-   3943 -   EXOPLANETS  - Earth size with atmospheres?  -    Earth-size exoplanet spotted just 72 light-years away.  Researchers searching for transiting exoplanets (those that cross their host star's face from our perspective) has made its latest discovery, an Earth-size body just 72 light-years away from us.


------------  3943  -  EXOPLANETS  - Earth size with atmospheres?

-  “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 Kepler space telescope.

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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 whether those planets form and evolve just like the planets around solar-type stars.   Solar-type stars are stars akin to our sun.

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-    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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-    The more exoplanets we discover and the more we learn about their star systems, the higher the chance we'll find more potentially habitable exoplanets. 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.

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-   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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-    Astronomers discover another potential habitable exoplanet only 31 light-years from Earth.   Preliminary estimates 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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-   The exoplanet named “Smertrios” is a hot Jupiter exoplanet with an atmosphere that defies expectations.  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.

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-   Observations of the distant exoplanet “HD149026b”,  “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, the James Webb Space Telescope 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.  Astronomers have seen more diverse atmospheric compositions in gas giant exoplanets previously, but the composition of the atmosphere of HD149026b is off the charts.

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-    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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-     Smertrios, is a so-called hot Jupiter, 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.

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-     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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-    We have 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.

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-  These discocveries 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 2, 2023     EXOPLANETS  - Earth size with atmospheres?             3943                                                                                                                         

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--------------------- ---  Sunday, April 2, 2023  ---------------------------

 

 

 

 

         

 

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