A heavy ring of dust surrounding the Sun on the orbital path of Venus has just been revealed in more detail so far, thanks to instruments carried by the Parker solar probe.
The virgin images of white light, taken from the orbit of Venus, show the ring in its entirety. These are vital data for understanding this ring and the dynamics of the solar system and its gravitational interactions.
“It’s the first time a ring of circumsolar dust in the inner solar system can be revealed in all its glory in‘ white light ’images,” said astronomer William Stenborg of the U.S. Naval Research Laboratory. “I find it pretty special.”
(Stenborg et al.)
The Solar System is a truly dusty place. Everything was formed from dust (and gas); much of the dust was integrated into planets and asteroids and something else (not to mention the Sun); it is often shaken again.
Asteroids and comets are like cosmic pepper sacks and splatter their surrounding space wherever they go. Recent research found that Mars could be spraying things everywhere during the huge global storms that occur every year.
All this dust can only be derived, but can sometimes be snatched in orbital resonance with a planet; that is, it orbits the same path, with an orbital period that has a ratio of a single integer to that of the planet.
The Earth has an important resonant dust ring; recently, scientists found evidence that Mercury also has it. And Venus’ dust ring has been known, and even partially observed, by the German-American joint solar mission Helios and NASA’s STEREO solar mission, for some time.
Cue the Parker Solar Probe, equipped with an instrument called the Wide-Field Imager for Solar Probe (WISPR). WISPR consists of two heliospheric images of visible light designed to imagine the interplanetary medium for studying the solar wind: the constant stream of charged particles emanating from the Sun.
Because the interplanetary dust is so bright with reflected sunlight, it outstrips the solar wind, so special image processing is applied to eliminate background noise in solar wind observations. This also means that WISPR is only able to observe the ring of Venus resonance dust.
Of course, during normal operations, the dust ring would be automatically extracted from the data. Parker performed some maneuvers in August and September 2019 to manage his momentum, prompting the movement of WISPR cameras, and a bright streak appeared on the resulting images.
At first, astronomers thought it was something else, such as a glowing helmet coil firing from an active region of the Sun or even an image processing error. It was too large to become a helmet streamer, and printing processes were also ruled out. The next step was to look at what else is in this space, and that was when they found that the line aligned perfectly with the orbit of Venus.
Since the glow is also consistent with the scattering of light by dust, the team concluded that the most likely explanation is the planet’s resonant dust ring.
The data can be extremely useful. Scientists think that interplanetary dust could be a mechanism for transporting molecules from the solar system, a means by which materials released from asteroids or comets are directed to other bodies.
We still don’t know how these dust rings formed or where they came from, so the more information we have, the closer we can get to finding out.
“One idea is that dust rings form naturally from the primordial cloud, but several researchers argue that the gravity of each planet has gradually trapped particles, even asteroid particles or comets within its orbit,” explained astrophysicist Russell Howard of the United States Naval Research Laboratory. .
Another possibility is that the dust rings rotate constantly; collisions between grains could expel some of the old dust from orbit, while new dust comes from elsewhere.
There is also another mystery with the Venus ring. Analysis of the data from previous observations suggested that there was much more dust in the Venus resonance ring that could not be easily explained. Recently, a research team conducted some models and determined that the best explanation for the amount of dust is a group of asteroids that do not share the orbit of Venus.
We have not yet found these asteroids, so this hypothesis is far from being confirmed. Who knows, maybe Parker will spot them; or perhaps the probe will lead us to another explanation of the phenomenon. Either way, it will be exciting.
“We’re learning things about the dynamics, the exchanges, of dust particles all over the heliosphere that we didn’t know before the Parker Solar Probe,” Stenborg said.
The research has been published in The Astrophysical Journal.