Meteors that streak through the sky leaving behind a persistent afterglow have long intrigued astronomers. A recent study published in the Journal of Geophysical Research: Space Physics sheds light on the mystery behind these long-lasting meteor trails.
Contrary to previous assumptions, the key factor that determines whether a meteor will leave a persistent train is its height in the atmosphere, not its speed or brightness. This discovery was made possible through the first systematic survey of persistent trains conducted by astrophysicist Logan Cordonnier and his team.
Using a setup that consisted of a hacked mini-fridge housing an upward-facing camera, a fisheye lens, and a computer, the researchers monitored the sky over New Mexico for nearly two years. During this time, they recorded nearly 7,500 meteors, with about 850 of them leaving persistent trains. Surprisingly, trains were found to be more common than previously thought, with about 1 in 8 meteors leaving a train and 1 in 19 lasting longer than five minutes.
The study found that meteors that penetrated to altitudes of 90 kilometers were more likely to leave trains compared to those that burned up at higher altitudes. The availability of ozone at this altitude was identified as a key factor in the formation of persistent trains. While most of the persistent trains were previously believed to be formed by fast, bright meteors, the research showed that slower meteors were also capable of leaving behind these glowing trails.
The chemistry behind the formation of persistent trains remains an intriguing question for scientists. Some atmospheric physicists suggest that tiny, charged dust grains knocked off the meteorite could create an electric field that helps maintain the shape of the train. Further investigations into the data collected from this survey and others could provide valuable insights into this phenomenon.
These findings open up new avenues for studying the chemistry of the Earth’s atmosphere, particularly at altitudes that are challenging to probe using traditional methods. The continuous occurrence of persistent trains offers scientists a unique opportunity to observe and understand this elusive atmospheric layer. By leveraging the data from this survey, researchers hope to unravel the secrets behind the formation and maintenance of these captivating meteor trails.
