Meteor Activity Outlook for 14-20 January 2023

Aaron Morris captured this bursting sporadic fireball at 01:56 UT on August 1, 2022 (21:56 EDT July 31), from Griffin, Georgia, USA. ©Aaron Morris

During this period, the moon reaches its last quarter phase on Sunday January 15th. On that date the half-illuminated moon will rise near 01:00 local standard time and will remain in the sky the remainder of the night. As the week progresses the moon’s phase will lessen plus it will rise approximately 45 minutes later with each passing night. During the last half of this period the crescent moon will not be a factor to inhibit meteor observing. The estimated total hourly rates for evening observers this week should be near 3 as seen from mid-northern latitudes (45N) and 3 as seen from tropical southern locations (25S) For morning observers, the estimated total hourly rates should be near 12 as seen from mid-northern latitudes (45N) and 7 as seen from tropical southern locations (25S). 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. Morning rates are reduced during this period due to interfering moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.

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 January 14/15. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. I have also included charts of the sky that display the radiant positions for evening, midnight, and morning. The center of each chart is the sky directly overhead at the appropriate hour. These charts are oriented for facing south but can be used for any direction by rotating the charts to the desired direction. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant, so it is best to center your field of view so that the radiant lies at the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.

These sources of meteoric activity are expected to be active this week.

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The large Anthelion (ANT) is currently centered at 08:28 (127) +17. This position lies in central Cancer, just south of the faint star known as theta Cancri. Due to the large size of this radiant, these meteors may also be seen from eastern Gemini and western Leo as well as Cancer. This radiant is best placed near 01:00 local standard time (LST) when it lies on the meridian and is highest in the southern sky. Rates at this time should be near 2 per hour as seen from the northern hemisphere and 1 per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Comae Berenicids (COM) is a shower of long duration active from December 5th all the way through February 4th. Maximum occurred near December 19th when rates may have reached 3 an hour. During this period, I would expect hourly rates of 1 from a radiant located at 12:19 (185) +19. This position lies in central Coma Berenices, 1 degree north of the faint star known as 11 Comae Berenices. These meteors are best seen near 0400 LST when the radiant lies highest above the southern horizon. At 63 km/sec. the Comae Berenicids produce mostly swift meteors. These meteors are also known as the December Leonis Minorids.

The gamma Ursae Minorids (GUM) are another source discovered by Dr. Peter Brown and associates. These meteors are active from January 10-22, with maximum activity occurring near January 18. The radiant is currently located at 14:56 (224) +69, which places it southern Ursa Minor 3 degrees southwest of the 3^rd magnitude star known as Pherkad (gamma Ursae Minoris). These meteors are best seen during the last few hours before dawn, when the radiant lies highest above the northern horizon. Rates may reach 1 per hour on the morning of the 18^th as seen from the Northern Hemisphere. Unfortunately these meteors are not visible from the Southern Hemisphere. These meteors encounter the atmosphere at 31 km/sec., which would produce meteors of medium-slow velocity.

Those interested in detecting meteor via radio waves may start noticing activity from the Capricornid/Sagittarids (DCS). These meteors can be detected from January 13 through February 4, with maximum activity occurring near February 1^st. These meteors would be best detected during the morning hours of 8-10am, when the radiant lies approximately half-way up in the sky. It should be noted that meteors do not emit radio waves, but they act as mirrors and reflect radio waves from distant transmitters which aren’t heard otherwise. This is called forward scatter, opposed to backscatter where the transmitter and receiver are at the same place (radar). For practical reasons the frequency range 50 – 150 MHz (wavelength 6 m – 2 m) is used. This includes amongst others the FM band and TV transmitters which haven’t switched yet to digital. Most reflections are short (less than a second), but brighter meteors can cause reflections lasting minutes. The shortest radio reflections are caused by faint meteors, fainter than visual ones. Radio reflections can be observed regardless of daylight or clouds, allowing more complete views of streams. For those interested in meteor observing via radio waves we invite you to visit RMOB.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 6 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would also be near 6 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced by moonlight during this period. 

The list below offers the information in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.

Class Explanation: A scale to group meteor showers by their intensity:

• Class I: the strongest annual showers with Zenith Hourly Rates normally ten or better.
• Class II: reliable minor showers with ZHR’s normally two to ten.
• Class III: showers that do not provide annual activity. These showers are rarely active yet have the potential to produce a major display on occasion.
• Class IV: weak minor showers with ZHR’s rarely exceeding two. The study of these showers is best left to experienced observers who use plotting and angular velocity estimates to determine shower association. These weak showers are also good targets for video and photographic work. Observers with less experience are urged to limit their shower associations to showers with a rating of I to III.