Image: © Artsiom Petrushenka/Stock.adobe.com
Astronomers have snapped photos of a massive asteroid trail in our solar system, which has eluded them for decades.
A camera on board the NASA Parker Solar Probe has captured footage of the asteroid responsible for the Geminid meteor shower. Developed by the US Naval Research Laboratory (NRL), the Wide-Field Imager for Solar Probe (WISPR) was able to see the dust trail coming from asteroid 3200 Phaethon, which astronomers have spent decades searching for.
The data captured by WISPR determined that the dust trail weighs approximately 1bn tons and measures more than 22m km in length. These findings, according to NRL’s Karl Battams, raise questions about the trail’s origins.
“Something catastrophic happened to Phaethon a couple of thousand years ago and created the Geminid meteor shower,” he said. “There’s no way the asteroid is anywhere near active enough when it is near the sun to produce the mass of dust we are seeing, so we are confident that WISPR is seeing part of the Geminid meteor stream.”
The WISPR camera showing the dust trail of asteroid 3200 Phaethon near the sun on 5 November 2018. The trail is visible for the first time in the region where the white dots are omitted. Image: US Navy/Brendan Gallagher and Guillermo Stenborg
A powerful camera
The WISPR camera records visible-light images of the solar corona and solar outflow in two overlapping cameras, which together cover more than 100 degrees of angular width from the sun.
“[NRL’s imagers] allow you to see near-sun outflows massively fainter than the sun itself, which would otherwise blind our cameras,” Battams added. “And in this case, you can also see solar system objects extremely close to the sun, which most telescopes cannot do.”
The Geminid meteor shower is one of the big stargazing events of the year, occurring in mid-December. It is noted for producing 120 or more meteors per hour, which travel at around 35km per second and are often brightly coloured.
Classed as a near-Earth object, 3200 Phaethon has a wildly eccentric orbit, quite different to many other asteroids, and enters between the orbits of Mars and Jupiter.
