Meteor Activity Outlook for March 6-12, 2010
March 7, 2010 3 Comments
The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.
March is the slowest month for meteor activity. No major annual showers are active and only two very weak minor showers produce activity this month. The sporadic rates continue a slow decline as seen from the mid-northern latitudes and mid-southern rates reach a first half minimum. There is not much to look forward to this month expect for the evening fireballs that seem to peak this time of year from the northern hemisphere. This could be due to the fact the antapex radiant lies highest above the horizon this time of year during the evening hours.
During this period the moon reaches its last quarter phase on Sunday March 7th. At this time the moon lies ninety degrees west of the sun and rises near midnight local standard time (LST). The moon will be a nuisance this weekend, but as the week progresses, its impact lessens. The estimated total hourly rates for evening observers this week is ~2 for those in the northern hemisphere and ~3 for those south of the equator. For morning observers the estimated total hourly rates should be ~7 from the northern hemisphere and ~9 as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity.
The radiant positions and rates listed below are exact for Saturday night/Sunday morning March 6/7. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The wide Antihelion (ANT) radiant is now centered at 11:56 (179) -01. This area of the sky lies in western Virgo, three degrees southeast of the fourth magnitude star Beta Virginis. This radiant is best placed near 0100 local standard time (LST) when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from eastern Leo, Sextans, Crater, or Virgo could be a candidate for this shower. Rates at this time should be ~2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.
Gamma Normids (GNO)
The Gamma Normids (GNO) is a weak shower best seen from the southern hemisphere. This shower is only visible south of forty degrees north latitude. The further one is located south (down to 50S) the better the radiant is situated in the sky. Expected rates from the southern hemisphere is only 1 per hour, even with the radiant located high in the sky. The current radiant position lies at 16:12 (243) -52. This position lies in central Norma, two degrees southwest of the fourth magnitude star Gamma Normae. The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 56km/sec. the Gamma Normids would produce mostly swift meteors.
The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.
Shower Name RA DEC Vel Rates km/s NH SH ANT Antihelions 11h 56m -01 30 2 2 GNO Gamma Normids 16h 12m -52 56 <1 1 RA - Right Ascension DEC - Declination Vel - Velocity relative to Earth (in km per sec) Rates - Rate of visible meteors per hour from a dark site NH - Northern Hemisphere SH - Southern Hemisphere