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Parker Solar Probe Captures First Complete View of Venus Orbital Dust Ring
Illustration of ±·“”³§“”ās Parker Solar Probe, operated by Johns Hopkins APL, orbiting close to Venus (left) and the faint glow of the planetās dust ring, which closely follows Venusā orbit around the Sun.
Credit: Johns Hopkins APL/Ben Smith
±·“”³§“”ās captured the first complete view of Venusā dust ring, a band of particles that stretches for the entirety of the planetās path around the Sun. The new images, , cover nearly the entire 360-degree view of the ring, completing a picture that scientists had seen only hints of before, with images from the Helios probes in the 1970s and multiple observations from ±·“”³§“”ās twin Solar Terrestrial Relations Observatory (STEREO) probes from 2007 to 2014.
āThis is the first time that a circumsolar dust ring in the inner solar system could be revealed in its full glory in āwhite lightā images,ā said study lead author Guillermo Stenborg from the U.S. Naval Research Laboratory in Washington, D.C. āI find that pretty special.ā
While Parker Solar Probeās chief objective is to study the Sunās corona and solar wind, the team planned from the missionās outset to try and capture images of Venusā dust ring using the spacecraftās Wide-field Imager for Parker Solar Probe, or WISPR, instrument.
With two telescopes that together provide a field of view of more than 95 degrees, WISPR was built to capture wide-angle images of the solar wind in white light. Initially, the dust ring was revealed using images from the spacecraftās third orbit around the Sun in August and September 2019, when it performed a series of rolling maneuvers to help manage its momentum. Those rolls incidentally made seeing the ring possible because it allowed for customized image processing to reveal faint, stationary features.
āThat process didnāt erase the dust ring from the images,ā as seems to have happened with images from the first two orbits, when the spacecraft didnāt perform those rolling maneuvers, explained Parker Solar Probe Project Scientist from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. With that realization, the team went back and reprocessed the earlier images, and there, indeed, was the ring.
āItās funny that spacecraft operations can sometimes lead to the discovery of new things,ā Raouafi remarked, smiling. āItās kind of amazing.ā
Combined images from Parker Solar Probeās WISPR instrument of Venusā dust ring on Aug. 25, 2019, showing Mercury, Venus, Earth and part of the Milky Way galaxy. The images show the dust ring perfectly aligns with Venusā orbit (red dots).
Credit: Stenborg et al.
The team at first thought the ring ā which when resolved appears as a bright band stretching across the blackness of space ā was a streamer, a coronal structure that glows thanks to electrons tied up within it. But that bright band continued to the outermost edge of WISPRās field of view, very unlike a streamer, whose brightness would fall off the farther it stretches from the Sun.
Eliminating the possibility that it was an artifact from the image processing, the researchers plotted the orbits of several planetary objects known to have circumsolar dust rings (Earth, Venus and an odd group of asteroids called the Karin family) and found the bright band lined up perfectly with Venusā orbit.
The Venus dust ring, like Earthās ring and Mercuryās ostensible ring, is made up of microscopic particles thought to be from the cloud that formed our solar system, as well as the continuous crumble of comets and collision of asteroids.
An animation showing Parker Solar Probeās path around the Sun during its third orbit from August to September 2019. While the animation omits the zodiacal dust, which would shine brightly in regions near the Sun, it depicts the faint dust rings that align with Earthās, Venusā and, purportedly, Mercuryās solar orbits.
Credit: Johns Hopkins APL/Ben Smith