NASA’s Juno Mission Provides Infrared Tour of Jupiter’s North Pole

Scientists
working on NASA’s Juno mission to Jupiter shared a
3-D infrared movie depicting
densely packed cyclones and
anticyclones that permeate the planet’s polar
regions, and the
first detailed
view of a dynamo, or engine, powering the
magnetic field for any planet beyond
Earth. Those are among
the items unveiled during
the European Geosciences Union
General Assembly in Vienna, Austria, on Wednesday,
April 11.

In this animation the viewer is taken low over Jupiter’s north
pole to illustrate the 3-D aspects of the region’s central
cyclone and the eight cyclones that encircle it. The movie
utilizes imagery derived from data collected by the Jovian
Infrared Auroral Mapper (JIRAM) instrument aboard NASA’s Juno
mission during its fourth pass over the massive planet.
Infrared cameras are used to sense the temperature of Jupiter’s
atmosphere and provide insight into how the powerful cyclones
at Jupiter’s poles work. In the animation, the yellow areas are
warmer (or deeper into Jupiter’s atmosphere) and the dark areas
are colder (or higher up in Jupiter’s atmosphere). In this
picture the highest “brightness temperature” is around 260K
(about -13°C) and the lowest around 190K (about -83°C). The
“brightness temperature” is a measurement of the radiance, at 5
µm, traveling upward from the top of the atmosphere towards
Juno, expressed in units of temperature.

Juno mission scientists have taken data collected by the
spacecraft’s Jovian InfraRed Auroral Mapper (JIRAM) instrument
and generated the
3-D fly-around of the Jovian world’s north
pole. Imaging in the infrared part of the
spectrum, JIRAM
captures light emerging from deep inside Jupiter equally well,
night or day. The instrument probes the weather layer down to
30 to 45 miles
(50 to 70 kilometers) below Jupiter’s cloud
tops. The imagery will help the
team understand the forces at
work in the animation – a north pole dominated by
a central
cyclone surrounded by eight circumpolar cyclones with
diameters
ranging from 2,500 to 2,900 miles (4,000 to 4,600
kilometers).

NASA’s Juno mission has provided the first view of the dynamo,
or engine, powering Jupiter’s magnetic field. The new global
portrait reveals unexpected irregularities and regions of
surprising magnetic field intensity. Red areas show where
magnetic field lines emerge from the planet, while blue areas
show where they return. As Juno continues its mission, it will
improve our understanding of Jupiter’s complex magnetic
environment.

“Before Juno, we could only guess what Jupiter’s poles would
look like,” said
Alberto Adriani, Juno co-investigator from
the Institute for Space Astrophysics
and Planetology, Rome.
“Now, with Juno flying over the poles at a
close distance it
permits the collection of infrared imagery on Jupiter’s polar
weather patterns and its massive cyclones in unprecedented
spatial resolution.”

Another
Juno investigation discussed during the media briefing
was the team’s latest
pursuit of the interior composition of
the gas giant. One of the biggest pieces
in its discovery has
been understanding how Jupiter’s deep interior rotates.

“Prior
to Juno, we could not distinguish between extreme
models of Jupiter’s interior
rotation, which all fitted the
data collected by Earth-based observations and
other deep
space missions,” said Tristan Guillot, a Juno co-investigator
from the Université Côte
d’Azur, Nice, France. “But Juno is
different — it orbits the planet from pole-to-pole
and gets
closer to Jupiter than any spacecraft ever before. Thanks to
the
amazing increase in accuracy brought by Juno’s gravity
data, we have
essentially solved the issue of how Jupiter’s
interior rotates: The zones and
belts that we see in the
atmosphere rotating at different speeds extend to
about 1,900
miles (3,000 kilometers).

An infrared view of Jupiter’s North Pole. The movie utilizes
imagery derived from data collected by the Jovian Infrared
Auroral Mapper (JIRAM) instrument aboard NASA’s Juno mission.
The images were obtained during Juno’s fourth pass over
Jupiter. Infrared cameras are used to sense the temperature of
Jupiter’s atmosphere and provide insight into how the powerful
cyclones at Jupiter’s poles work. In the animation, the yellow
areas are warmer (or deeper into Jupiter’s atmosphere) and the
dark areas are colder (or higher up in Jupiter’s atmosphere).
In this picture the highest “brightness temperature” is around
260K (about -13°C) and the lowest around 190K (about -83°C).
The “brightness temperature” is a measurement of the radiance,
at 5 µm, traveling upward from the top of the atmosphere
towards Juno, expressed in units of temperature.

“At
this point, hydrogen becomes conductive enough to be
dragged into near-uniform
rotation by the planet’s powerful
magnetic field.”

The
same data used to analyze Jupiter’s rotation contain
information on the
planet’s interior structure and
composition. Not knowing the interior rotation
was severely
limiting the ability to probe the deep interior. “Now our work
can
really begin in earnest — determining the interior
composition of the solar system’s
largest planet,” said
Guillot.

At the meeting,
the mission’s deputy-principal investigator,
Jack Connerney of the Space Research Corporation, Annapolis,
Maryland, presented the
first detailed view of the dynamo, or
engine, powering the magnetic field of
Jupiter.

Connerney
and colleagues produced the new magnetic field model
from measurements made
during eight orbits of Jupiter. From
those, they derived maps of the magnetic
field at the surface
and in the region
below the surface where the dynamo is
thought to originate. Because Jupiter is
a gas giant,
“surface” is defined as one Jupiter radius, which is about
44,400
miles (71,450 kilometers).

These maps provide an extraordinary
advancement in current
knowledge and will guide the science team in planning
the
spacecraft’s remaining observations.

“We’re finding that Jupiter’s magnetic field is unlike
anything previously imagined,”said
Connerney. “Juno’s
investigations of the magnetic environment at Jupiter represent
the
beginning of a new era in the studies of planetary
dynamos.”

The map Connerney’s team made of the
dynamo source region
revealed unexpected irregularities, regions of surprising
magnetic field intensity, and that Jupiter’s magnetic field is
more complex in
the northern hemisphere than in the southern
hemisphere. About halfway between
the equator and the north
pole lies an area where the magnetic field is intense
and
positive. It is flanked by areas that are less intense and
negative. In the
southern hemisphere, however, the magnetic
field is consistently
negative, becoming more and more intense
from the equator to the pole.

The researchers
are still figuring out why they would see
these differences in a rotating
planet that’s generally
thought of as more-or-less fluid.

“Juno is only about one third the way through its planed
mapping mission and already we are beginning to discover hints
on how Jupiter’s
dynamo works,” said Connerney. “The team is
really anxious to see the data from
our remaining orbits.”

Juno has logged nearly 122 million miles (200 million
kilometers) to complete those 11 science passes since entering
Jupiter’s orbit
on July 4, 2016. Juno’s 12th science pass will
be on May 24.

NASA’s Jet Propulsion Laboratory, Pasadena, California,
manages
the Juno mission for the principal investigator, Scott
Bolton, of the Southwest
Research Institute in San Antonio.
Juno is part of NASA’s New Frontiers
Program, which is managed
at NASA’s Marshall Space Flight Center in Huntsville,
Alabama,
for NASA’s Science Mission Directorate. The Italian Space
Agency
(ASI), contributed two instruments, a Ka-band frequency
translator (KaT) and
the Jovian Infrared Auroral Mapper
(JIRAM). Lockheed Martin Space, Denver,
built the spacecraft.

https://www.nasa.gov/juno

https://www.missionjuno.swri.edu

The public can follow the mission on Facebook and Twitter at:

https://www.facebook.com/NASAJuno

https://www.twitter.com/NASAJuno

More information on Jupiter can be found at:

https://www.nasa.gov/jupiter

News Media Contact

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov

JoAnna Wendel
NASA Headquarters, Washington
202-358-1003
joanna.r.wendel@nasa.gov

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