UVS images faint auroral rings that likely come from at edge of gas giant’s magnetosphere.
The SwRI-led Ultraviolet Spectrograph (UVS) orbiting Jupiter aboard NASA’s Juno spacecraft has actually spotted brand-new faint aurora functions, identified by ring-like emissions, which broaden quickly gradually. SwRI researchers figured out that charged particles originating from the edge of Jupiter’s huge magnetosphere activated these auroral emissions.
“We think these newly discovered faint ultraviolet features originate millions of miles away from Jupiter, near the Jovian magnetosphere’s boundary with the solar wind,” stated Dr. Vincent Hue, lead author of a paper accepted by the Journal of Geophysical Research: Space Physics. “The solar wind is a supersonic stream of charged particles emitted by the Sun. When they reach Jupiter, they interact with its magnetosphere in a way that is still not well understood.”
Both Jupiter and Earth have electromagnetic fields that supply defense from the solar wind. The more powerful the electromagnetic field, the bigger the magnetosphere. Jupiter’s electromagnetic field is 20,000 times more powerful than Earth’s and produces a magnetosphere so big it starts to deflect the solar wind 2-4 million miles prior to it reaches Jupiter.
“Despite decades of observations from Earth combined with numerous in-situ spacecraft measurements, scientists still do not fully understand the role the solar wind plays in moderating Jupiter’s auroral emissions,” stated SwRI’s Dr. Thomas Greathouse, a co-author on this research study. “Jupiter’s magnetospheric dynamics, the motion of charged particles within its magnetosphere, is largely controlled by Jupiter’s 10-hour rotation, the fastest in the solar system. The solar wind’s role is still debated.”
One of the objectives of the Juno objective, just recently authorized by NASA for an extension up until 2025, is to check out Jupiter’s magnetosphere by determining its auroras with the UVS instrument. Previous observations with the Hubble Space Telescope and Juno have actually permitted researchers to identify that the majority of Jupiter’s effective auroras are created by internal procedures, that is the movement of charged particles within the magnetosphere. However, on many celebrations, UVS has actually spotted a faint kind of aurora, identified by rings of emissions broadening quickly with time.
“The high-latitude location of the rings indicates that the particles causing the emissions are coming from the distant Jovian magnetosphere, near its boundary with the solar wind,” stated Bertrand Bonfond, a co-author on this research study from Belgium’s Liège University. In this area, plasma from the solar wind typically communicates with the Jovian plasma in such a way that is believed to form “Kelvin-Helmholtz” instabilities. These phenomena take place when there are shear speeds, such as at the user interface in between 2 fluids moving at various speeds. Another possible prospect to produce the rings are dayside magnetic reconnection occasions, where oppositely directed Jovian and interplanetary electromagnetic fields assemble, reorganize and reconnect.
Both of these procedures are believed to create particle beams that might take a trip along the Jovian electromagnetic field lines, to ultimately speed up and set off the ring auroras on Jupiter.
“Although this study does not conclude what processes produce these features, the Juno extended mission will allow us to capture and study more of these faint transient events,” Hue stated.#
The Jet Propulsion Laboratory, a department of Caltech in Pasadena, California, handles the Juno objective for the primary private investigator, Dr. Scott J. Bolton, of SwRI. Juno belongs to NASA’s New Frontiers Program, which is handled at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the firm’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver constructed and runs the spacecraft.