Dr. Peter Jenniskens of the SETI Institute and NASA’s Ames Research Center and his colleagues say they can detect meteor showers from the debris in the path of comets with orbital periods less than 4,000 years.
The meteoroid stream of long-period comet Thatcher from CAMS data; outer blue ellipse is the orbit of Neptune. Image credit: P. Jenniskens / SETI Institute.
Low-light video cameras are used to track the motion of meteors in the atmosphere of Earth by triangulation and to calculate the meteoroid orbit in space.
In recent years, the Cameras for Allsky Meteor Surveillance (CAMS) low-light camera network was greatly expanded and, together with other video networks, significantly increased the total video meteoroid orbit database.
“This creates a situational awareness for potentially hazardous comets that were last near-Earth orbit as far back as 2,000 BCE,” said Dr. Jenniskens, who is the lead of the CAMS project.
Dr. Jenniskens and co-authors searched the CAMS database for meteor showers associated with known long-period comets.
“Until recently, we only knew five long-period comets to be parent bodies to one of our meteor showers, but now we identified nine more, and perhaps as many as 15,” they said.
The astronomers also found that long-period comet meteor showers can last for many days.
“This was a surprise to me. It probably means that these comets returned to the Solar System many times in the past, while their orbits gradually changed over time,” Dr. Jenniskens said.
The CAMS data also revealed that the most dispersed meteor showers show the highest fraction of small meteoroids.
“The most dispersed showers are probably the oldest ones,” Dr. Jenniskens noted.
“So, this could mean that the larger meteoroids fall apart into smaller meteoroids over time.”
Comets comprise only a small fraction of all impactors on Earth, but astronomers believe they caused some of the biggest impact events over Earth’s history because they can be big and the fact that their orbits are such that they can impact at high speed.
“In the future, with more observations, we may be able to detect fainter showers and trace the orbit of parent comets on even longer orbits,” Dr. Jenniskens said.
The results were published in the journal Icarus.
Peter Jenniskens et al. 2021. Meteor showers from known long-period comets. Icarus 365: 114469; doi: 10.1016/j.icarus.2021.114469