- 4311 -
JUPITER get to EXOPLANETS? - Io gets its status as the solar system's
most volcanic body as a result of the immense gravity of Jupiter, the most
massive planet in the solar system, in addition to the gravitational influence
of the other large Jovian moons , Europa, Ganymede and Callisto.
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-------------------------
4311 - JUPITER get to EXOPLANETS?
- Astronomers Test
an “exoplanet instrument” on Jupiter.
The European Southern Observatory’s Very Large Telescope (VLT) has a
high-resolution spectrograph called “ESPRESSO”, designed specifically to
detecting and characterize exoplanets.
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- Astronomers
recently ran a test with the instrument, studying the atmosphere and winds of
Jupiter. They used “Doppler velocimetry” to measure the reflection of light
from the Sun in the planet’s clouds, allowing for instantaneous measurement of
the clouds’ wind speeds. The technique has also been used on Venus and will
guide the future study of exoplanets.
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- ESPRESSO is the
“Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic
Observations”. The instrument combines
the light from all four of the VLT telescopes, capturing the light from each of
the 8.2 meter mirrors in the four Unit Telescopes of the VLT. That combination
makes ESPRESSO, in effect, the largest optical telescope in the world.
-
- This type of
observing power is being used to measure the variation of the fundamental
physical constants in the Universe and to analyze the chemical composition of
stars in nearby galaxies. And as a planet hunter, it can search for Earth twins
in the habitable zone of solar-like stars.
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- Astronomers wanted
to test out a new method which might allow them to study and monitor the
atmospheres on distant gaseous exoplanets.
The test was conducted in July 2019, and for five hours, the team
pointed the VLT at the equatorial zone of Jupiter, where light clouds are
located at a higher altitude, and at the planet’s north and south equatorial,
which correspond to descending air and which it forms bands of dark, warmer
clouds in a deeper layer of the atmosphere.
-
- The difficulty was
related to the fact that we were determining winds with an accuracy of a few
meters per second when Jupiter’s rotation is on the order of ten kilometers per
second at the equator and, to complicate matters because it is a gaseous
planet, and not a rigid body, it rotates at different speeds depending on the
latitude of the point we observe.
-
- With ESPRESSO, the
team was able to measure winds on Jupiter from 60 to 428 km/h with an
uncertainty of less than 36 km/h.
Comparing the results between cloud-tracking methods, based on previous
reference observations, and our new Doppler velocimetry approach, the team
found a good agreement between them, demonstrating the effectiveness of this
technique.
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- Jupiter’s
atmosphere, at the level of the clouds visible from Earth, contains ammonia,
ammonium hydrosulfide and water, which form the distinct red and white
bands. The upper clouds, located in the
pressure zone of 0.6 to 0.9 bars, are made of ammonia ice. Water clouds form
the densest, lowest layer, and have the strongest influence on the dynamics of
the atmosphere.
-
- This paves the
way for exploration the atmospheres of distant exoplanets. While Jupiter is
“only” 43 light minutes away from Earth, the same technique should be feasible
for exoplanets that are hundreds to thousands of light years away.
-
- “SA Juno”
spacecraft reveals Jupiter's volcanic moon “Io” like never before in
spectacular new images. During its 57th
flyby of Jupiter, NASA's Juno spacecraft came closer to the planet's moon “Io”
than any other mission has in the last two decades.
-
- Passing within 930
miles of Io, the most volcanic body in the solar system, on December 30, 2023,
Juno was able to capture stunningly detailed images of the Jovian moon. The
only time a spacecraft has come closer to Io was in 2001, when NASA's Galileo
spacecraft passed 112 miles above Io's south pole.
-
- Juno, launched on
August 5, 2011, and reached Jupiter and its system of moons on July 4,
2016 after a 1.7 billion-mile journey. The purpose of the close passage
wasn't just to take some incredible images, however, but also to collect
important data about Io and its volcanism.
-
- By combining data
from this flyby with previous observations, the Juno science team is studying
how Io's volcanoes vary. They are
looking for how often they erupt, how bright and hot they are, how the shape of
the lava flow changes, and how Io's activity is connected to the flow of
charged particles in Jupiter’s magnetosphere.
-
- The “JunoCam”
instrument aboard the #JunoMission
acquired six images of Jupiter's moon Io during its close encounter . This
black-and-white view was taken at an altitude of about 1,500 miles.
-
- Io gets its status
as the solar system's most volcanic body as a result of the immense gravity of
Jupiter, the most massive planet in the solar system, in addition to the
gravitational influence of the other large Jovian moons , Europa, Ganymede and
Callisto.
-
- Together, the
Jovian moons and Jupiter pull and push on Io, generating tidal forces. These
tidal forces are so immense they can cause the surface of Io to flex intensely
enough to can rise and drop by extremes as great as 330 feet.
-
- As a result, the
surface of Io, a body roughly the same size as Earth's moon, is covered in
hundreds of active volcanoes that spew lava as high as dozens of miles above
Io.
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- Some of these
particles escape the thin, waterless atmosphere of the Jovian moon and are then
trapped by the magnetic fields of Jupiter, forming a hot torus of plasma around
the gas giant planet. This is just one
way that the volcanism of Io can impact the whole Jovian system, exemplifying
why the data that the Juno spacecraft has been collecting is so valuable to
planetary scientists.
-
- It won't be long
before Juno makes another close approach to Io. The spacecraft will once again
pass to within around 930 miles of the volcanic surface of this Jovian moon on
February 2, 2023.
-
- Subsequently more
and more distant, beginning with a passage around 6,830 miles away from Io and
culminating with a final flyby at around 62,100 miles .
-
- After the final
approach to Io, Juno will reach the end of its extended mission in September,
2025. At this time, the spacecraft will be intentionally crashed into the
atmosphere of Jupiter, concluding its 9-year study of the gas giant and its
moons.
-
-
January 10, 2023
JUPITER get to EXOPLANETS? 4311
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