Camelopardalid Meteor Shower Tonight: Earth to Intercept 'Dust Trails' Comet 209P/LINEAR For First Time

Rare Camelopardalid Meteor Shower This Weekend Is Full of Unknowns

Meteor expert Bill Cooke, head of Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Ala., 

For those of us at the NASA Meteoroid Environment Office (MEO), meteors — and meteor showers — are something to be taken seriously. Meteoroids pose a non-negligible risk to spacecraft and astronauts on extravehicular activities. A small 1 millimeter meteoroid moving at 20 kilometers per second has the punch of a bullet — so we spend a great deal of time on models and observations of the meteoroid environment, including meteor shower forecasting.

The state of the art has advanced considerably since the first forecasts for the Leonid meteor storms of 1999-2002, and researchers can now confidently predict Leonid, Perseid, and some other meteor shower outbursts with great precision, getting the times of the peaks to within just a few minutes and the meteor rates to within a factor of two.

We’ve come a long way since August 1993, when a space shuttle mission was actually delayed a few days because of the inability to predict how strong the Perseids would be that year. [New Meteor Shower from Comet 209P/LINEAR (Gallery)]

However, Mother Nature has ways of letting us know that there is still much to learn, 

Our forecast models do well at predicting shower activity caused by Halley family comets (Halley, Swift-Tuttle, Tempel-Tuttle, etc.), but are not so good when it comes to meteor showers caused by Jupiter family comets, such as Comet Giacobini-Zinner, the source of the Draconid meteor shower each October. The radar outburst of Draconids in 2012 was a big surprise to meteor researchers, as the forecast models did not show a large number of small particles from Giacobini-Zinner near Earth in October of that year. Like the Draconid parent, Comet 209P/LINEAR is a Jupiter family comet; it and its debris are perturbed by the giant planet Jupiter’s gravity, which adds complexity when we attempt to predict what will happen in the early morning hours of May 24.

The comet was not discovered until 2004, but computer models show that particles produced by its outgassing in the 18th, 19th, and early 20th centuries will intersect Earth’s path this year, but how do we go from the number of particles in the computer simulation to the actual number of meteors? Meteor shower forecasts are usually calibrated by running the model for past years and comparing its output to the observations of the actual meteor rates — but, what do you do when the shower has never been seen before?

This is the same sort of uncertainty that existed back in 1993, though the cause is different. With the Perseids, plenty of observations existed, but computerswere not yet powerful enough to sling millions of simulated particles off a simulated comet and track their paths until they intersected Earth; the situation is reversed with the 2014 May Camelopardalids— we have no past observations of this shower with which to calibrate the model. Observations of Comet 209P/LINEAR made since its discovery have shown that it is a poor dust (debris) producer.

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