Meteor Alert — Look to the sky this Sunday!

ORIONID METEORS TO PEAK SOON . . . BRIGHT DISPLAY IN THE OFFING?
From Joe Rao, Farmers’ Almanac Astronomer

This is an alert for all observers to watch for a possible unusual display of Orionid meteors. The Orionids are thought to result from the orbit of Halley’s Comet; some of the dust shaken from this famous comet as it runs its gigantic orbital loop from the Sun out to the orbit of the planet Neptune; a part of the same permanent river of meteoroids following the comet. Discovered in 1864, the Orionids were not linked to
This is actually our second encounter of the year with this rubble river. In early May we meet them on their way outward from their nearest approach to the Sun. The result is the Eta Aquarid meteor shower.

In October we encounter the part of the meteor stream moving inward toward the Sun. The orbit is in fact a retrograde one — moving opposite or contrary to our orbital direction of motion. That explains why the Orionids hit our atmosphere at a very high velocity — 42 miles per second — slower only than the November Leonids.

Another characteristic of the Orionids is that they start burning up very high in the atmosphere — probably because they are of lightweight material. This means they come from the diffuse surface of the comet, and not its core. Some Orionids are fireballs, but most are faint, and about 20-percent leave trains that persist for one or two seconds. Orionids meteors can be found between October 2 and November 7.

Traditionally, the peak of the Orionids comes on the morning of October 21, with an average hourly rate of about 25. Orion, now ahead of our journey around the Sun, doesn’t rise until 11:00 p.m., and the greatest number does not occur until around 4 or 5:00 a.m., when Orion is high in the south.

The Moon is at a bright waxing gibbous phase — normally a big drawback — but it will set at around 1:40 a.m. on Sunday morning; 2:45 a.m. on Monday morning . . . leaving the few hours before dawn breaks, dark for viewing.
A BLAST FROM THE PAST?

Here is why we should pay special attention to this year’s Orionids:

Last year’s Orionids were exceptional, and it is possible there may be a repeat this year. Last year, hourly rates exceeded the “normal” 25 per hour rate for five straight days . . . and between October 21 and 23, rates reached 50 to 60 per hour — more than twice the normal complement that can be expected from this display. Moreover, last years meteors were unusually bright, suggesting that the structure we passed through in 2006 was not part of the Orionid stream we normally sample.

So if you’re up …look the sky and you might just see a great show.

More meteor shower dates and times are here.

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Orionids meteor showers, Orionid, October meteors