If skies are clear, be sure to watch for a potential tau Herculid meteor outburst early next Tuesday morning.
With a little cosmic luck, we could potentially be in for a meteor storm of epic proportions this coming Monday night/Tuesday morning. We recently wrote about the possibility for an outburst from the tau Herculids on the night of May 30th/May 31st. As we’re now just under a week out from the shower, let’s look at the prospective for the shower, what went down during meteor storms of yore, and more.
tau Herculids: The Story Thus Far
The source of the shower is short period Comet 73P/Schwassmann-Wachmann 3. Despite the name, the radiant for the tau Herculids has actually now drifted from Hercules into the adjacent constellation of Boötes the Herdsman. Unfortunately, renaming the shower the ‘Boötids’ is also problematic, as there’s also already a June meteor shower of the same name. Today, the radiant for the shower sits about 8 degrees from the bright star Arcturus, in the direction of the globular cluster Messier 3 and Alkaid (Eta Ursae Majoris) located in the tip of the handle of the Big Dipper asterism.
The radiant for the tau Herculid meteors. Credit: The American Meteor Society.
What’s really getting meteor shower scientists excited is Earth’s 2022 encounter with the comet’s 1995 fragmentation stream. This event saw the comet dramatically increase 400-fold in brightness. Now, the comet is nowhere near the Earth next week—it’s actually 1.4 Astronomical Units (AU) distant, in fact—but the 1995 event should have laid down a decent particle stream for our fair planet to encounter.
As of writing this, the American Meteor Shower (AMS) has refined the key encounter time to 4:45-5:17 Universal Time (UT) / 12:45-1:17 AM U.S. Eastern Time EDT on the morning of Tuesday, May 31st or 9:45-10:17 PM Pacific Time PDT on the evening of Monday, May 30th. The radiant will be right at the zenith for Baja California around this time, though most of North and South America will be well-placed to witness any uptick in meteor activity. The Moon also reaches New the day prior on May 30th… another plus.
The elevation of the meteor shower radiant above the local horizon in degrees at the key time of 1:00 UT on the morning of May 31st. Credit: IMCCE
If we get a 10-fold increase from the tau Herculids we might see a Zenithal Hourly Rate (ZHR) of ~140 meteors per hour—similar to the annual Geminids or Perseids. If we reach a 100-fold or higher increase… well, things could get interesting.