- 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.
-
- 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.
-
- 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.
-
- 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.
-
- The
exoplanet is extremely close to K2-415, so close that it only takes about four
Earth days to complete an orbit.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- 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.
-
- Further
atmospheric observations of extrasolar planets with JWST will quantify this diversity
better and yield constraints on more complex trends that might exist.
-
- 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.
-
April 2, 2023 EXOPLANETS - Earth size with atmospheres? 3943
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