Not much is known about the Kappa Cygnid (KCG) meteor shower, and NASA’s Meteoroid Environments Office (MEO) is working to rectify that.
In 2014, during routine, daily monitoring, a particularly strong meteor shower caught the office’s attention, and they began to investigate.
“We regularly monitor the fireballs that we detect with our All Sky [Fireball] Network, and usually we see the same showers,” explained Althea Moorhead, aerospace technologist for planetary studies, part of MEO. “But in 2014, a strong peak suddenly stood out — probably in our top 10 in terms of most detectable showers.”
A little research told Moorhead that the shower her team spotted was the KCGs. Although the KCGs already had been discovered, not much literature exists, and despite speculations about the parent body, none have been confirmed.
By studying the KCGs and determining the parent body, Moorhead hopes to better predict the showers in the future.
“The Meteoroid Environments Office generates meteoroid forecasts, so that helps spacecraft programs mitigate the risk [to their craft] during shower outbursts,” said Moorhead. “We can tell them, ‘Look, this particular day, the flux is going to be a factor of two higher than normal,’ and they can say that’s fine or [determine] they need to do something about that.”
By examining the 2014 KCGs, Moorhead and the team were able to confirm the showers run on a seven-year cycle; that is, every seven years, the shower is more active and detectable. With this knowledge, the team can predict minimal activity in 2015, but expect an uptick again in 2021. These findings will help MEO improve its meteoroid forecast, which supports NASA’s missions.
The last time the shower was active, in 2007, the camera networks were in their infancy; in addition, even though radar was operational and saw the showers that year, the activity was much weaker. In fact, in 2014, the KCGs were five times stronger than in 2007 and 10 times stronger than in a typical year. This hints that there is an additional variability to these showers beyond the now-confirmed seven-year cycle.
“One of the most interesting things about the shower to me was that it had a diversity of orbital elements,” said Moorhead.
She explains that there is normally a spread in observations due to measurement uncertainty human error, but even after the team whittled down the findings, the spread still was fairly wide for a meteor shower. This means the KCGs could be composed of several sub-streams. If multiple sub-streams piled up, that could explain the active showing in 2014.
Determining a Parent Body
To try to determine the parent body, the team looked for asteroids and comets with similar orbits. According to Moorhead, the KCGs are in a region with a lot of asteroids with similar orbits, so determining the parent body is difficult.
The team made a list of all the asteroids that seemed most likely to be the parent body and conducted numerical simulations to determine if their orbital histories could create the orbit of the KCGs. Although the asteroids they checked could produce the KCG-like orbits, none matched exactly. It’s possible that the parent body has been lost, scattered to different orbits after a collision or hasn’t been discovered yet.
Even without an exact match, the team feels that two asteroids remain candidates: 2002 LV and 2001 MG1, with 2001 MG1 strongly favored.
“[But] there’s no smoking gun to say it’s definitely the parent body,” added Moorhead. “We’ll have to keep an eye on asteroid discoveries in coming years to see if anything can help us identify a parent body for sure.”