Meteor Activity Outlook for February 9-15, 2013
February 9, 2013 1 Comment
The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.
February offers the meteor observer in the northern hemisphere a couple of weak showers plus falling sporadic rates. This may not seem too exiting but you never know when surprises are in store. An errant earth-grazer from the Centaurid complex may shoot northward. Better yet, a bright fireball may light up the sky. February is the start of the fireball season, when an abundance of fireballs seem to occur. This lasts well into April and seems to occur mostly during the early evening hours.
Observers in the southern hemisphere are treated to the Alpha Centaurid peak on the 8th plus the entire Centaurid complex of radiants is active all month long. Sporadic rates also peak this month south of the equator this month adding to the celestial show.
During this period the moon reaches its new phase on Sunday February 10th. At this time the moon is located near the sun and is invisible at night. As the week progresses the waxing crescent moon will enter the evening sky but will not interfere with meteor observing. The estimated total hourly meteor rates for evening observers this week is near three as seen from the northern hemisphere and five as seen from south of the equator. For morning observers the estimated total hourly rates should be near nine from the mid-northern hemisphere and eighteen from the mid-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 (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning February 9/10. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.
The following showers are expected to be active this week:
The large Anthelion (ANT) radiant is currently centered at 10:16 (154) +09. This position lies in southwestern Leo, three degrees southeast of the first magnitude star Regulus (Alpha Leonis). These meteors may be seen all night long but the radiant is best placed near 0100 LST when it lies on the meridian and is highest in the sky. Rates at this time should be near two per hour as seen from the northern hemisphere and one per hour from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.
The Alpha Centaurids (ACE) are active from a radiant located at 14:10 (212) -60. This position lies in southeastern Centaurus, very close to the position occupied by the first magnitude star Hadar (Beta Centauri). These meteors cannot be seen north of the northern tropical regions. They are best seen from mid-southern latitudes where the radiant lies high in the sky near 0500 local summer time. This shower peaked on February 8th so current rates would be near three per hour as seen from the southern hemisphere. At 56km/sec. the Alpha Centaurids would produce mostly swift meteors.
Activity from the Beta Herculids begins on Wednesday morning February 13th. This also happens to be the morning of maximum activity. This shower was discovered by Juergen Rendtel and Sirko Molau using data from the IMO video database. This shower is active from the 13th through the 19th. On the 13th the radiant is located at 16:27 (247) +24. This position is located in western Hercules, three degrees north of the third magnitude star Kornephoros (Beta Herculis). These meteors are best seen near during the last dark hour before dawn when the radiant lies highest above the horizon in a dark sky. Rates would mostly likely be less than one shower member per hour, no matter your location. At 56 km/sec. the Beta Herculids would produce mostly swift meteors.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately seven sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near two per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fourteen per hour as seen from rural observing sites and four per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.
The list below presents a condensed version of the expected activity this week.
Rates and positions are exact for Saturday night/Sunday morning .
Anthelions (ANT) – 10:16 (154) +09 Velocity – 30km/sec.
Northern Hemisphere – 2 per hr. Southern Hemisphere – 1 per hr
Alpha Centaurids (ACE) – 14:10 (212) -60 Velocity – 56km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – 3 per hr
Beta Herculids (BHE) – 16:27 (247) +24 Velocity – 56km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr
American Meteor Society