Meteor Showers List, 2008-2009 January
Introduction
This is the separate listing of meteor showers referred to on page 4 of the Section's booklet Observing Meteors. Section members are encouraged to observe these because they are known to be genuinely active at the present time, and they produce visually-detectable rates. The list is based on the 2007 revision of the International Meteor Organization's (IMO's) Working List of Visual Meteor Showers, itself based on the most accurate global datasets ever collected, from 1988-2006. Amendments continue to be made using data collected since, to ensure the details remain as fully up-to-date as possible.
As we have discovered in the last two decades, meteor showers are not fixed things, but are constantly changing, some faster than others. As our understanding of their activity continues to improve, so we further refine the details on individual meteor showers. The information presented here was correct as of 2008 January 16. The showers are listed below in order of their maximum dates.
Shower Comments
The Quadrantids are named after the disused constellation Quadrans Muralis, the Wall Quadrant, now amalgamated into northern Boötes. The peak lasts only a few hours, so can be easily missed. It is due around 12h50m UT on 2009 January 3 (first quarter Moon). Peak ZHRs are occasionally variable (the highest recently was 180 in 1992), and a second, lesser, maximum has been found sometimes since 2000, mainly in radio observations about 9-12 hours after the main peak. Medium-speed meteors.
Best Lyrid rates are normally circa 15-20, but short-lived, more active bursts are sometimes recorded, most recently in 1982 (ZHR = 90). The maximum time can vary (expected between roughly 21h to 08h UT on 2008 April 21-22, partly overnight for Britain, but with a just-past-full Moon). Medium-speed to swift meteors. Probable parent body is Comet Thatcher of 1861 (orbital period about 415 years).
The η Aquarids are never easy to observe from the UK, as their radiant rises shortly before dawn, but occasional members are spotted by British watchers. Activity is marginally easier to note from these latitudes after the peak, when the radiant rises a little earlier. Very swift meteors, often with long paths because of their low radiant, and fine persistent trains. The stream was laid down by Comet 1P/Halley, along with their autumn twin the Orionids. Halley was last at perihelion in 1986 (period around 76 years). Perfect for new Moon.
The June Boötids produced an unexpected outburst in 1998, when ZHRs of 50-100+ were observed for over 12 hours, but rates were seen on just one date. Before this, only three returns of the shower were known, in 1916, 1921 and 1927. Another ZHR 50 outburst happened on 2004 June 23. The shower is associated with Comet 7P/Pons-Winnecke, due at perihelion again on 2008 September 26. Last quarter Moon will be a relatively minor problem later in the short midsummer nights for Britain for checking on activity, along with June's all-night twilight.
The δ Aquarids are strong enough to stand out from the summer ANT radiant, which is uncomfortably nearby to their north, though they are not seen at their best from the UK, due to their southerly radiant. Great care must be taken to separate them from ANT and CAP meteors in July-August. Medium-speed meteors. New Moon on August 1 is good news for covering their peak and that of the CAP.
The α Capricornids occasionally produce beautifully bright meteors, but their activity is never very high. Slow meteors.
From 1988-1999, the Perseids produced a double maximum, but from 2000-2003 only one main peak was seen. The primary peak was associated with Comet 109P/Swift-Tuttle's perihelion in 1992. A strong, early peak recurred in 2004. The normal maximum this time is expected on August 12 between 11h30m-14h UT, in daytime for Britain, while the waxing gibbous Moon will set around midnight UT. Swift meteors, often trained.
κ Cygnid rates are generally low, but occasional bright fireballs (possibly in periodic bursts every 6-7 years) have been seen from this source. Slow meteors. Ruined by full Moon.
The α Aurigids (possibly associated with Comet Kiess, last seen in 1911; period around 2000-2500 years), are part of a series of suspected minor showers with radiants in Aur, Cas, Per, Ari and Tri during the early autumn. All appear to be most active from late August to mid-September, and need more investigation, especially after the moonlit α Aurigid outburst on 2007 September 1 (ZHRs ~130). Very swift meteors. Perfect for new Moon in 2008.
The September Perseids are another of these near-Aur showers of very swift meteors (they used to be called the δ Aurigids), but here with a favourable first quarter Moon for their maximum.
δ Aurigid activity follows on directly from the September Perseids, and they are identical meteors. Their peak is very ill-defined. It may last from Sep 23 to Oct 3, giving low ZHRs. A waning to new Moon in late September assists much of this spell.
Draconid showers typically happen only when their parent comet, 21P/Giacobini-Zinner (period around 6.6 years), is at perihelion in the autumn, as in 1998, when short-lived ZHRs of circa 700 occurred. Other returns have given rates up to storm levels (the last storm was in 1946). A largely unexpected outburst happened in 2005 (the comet returned most recently that July), so worth checking in most years just in case. Very slow meteors, and apparently very fragile meteoroids. Possible maxima in 2008 fall on October 8 between 02h30m-19h30m UT, with a first quarter Moon.
The Orionids are linked to Comet 1P/Halley, like their May counterpart, the η Aquarids. ZHRs are usually quite good for 2-3 nights centred on their peak, and may be about 25 this year, from a recent analysis, but could be higher following the strong returns (ZHRs 40-60) in 2006 and 2007. A quite strong sub-maximum has been noted around October 17-18 as well. Their best has an unhelpful waning Moon. Very swift meteors, with good trains.
The Southern and Northern Taurids are both associated with weakly-active Comet 2P/Encke, which has the shortest orbital period of any comet known (3.3 years). The two showers give low rates, but occasional fireballs spice up their prospects, and in some years (as last in 2005, and next due this year) these can be especially prevalent in late October to early November (little Moon). Slow meteors. Full Moon is on November 13.
Possibly heightened Leonid activity is predicted for this year, with ZHRs maybe 50-100+ around 00h20m UT on November 17, or 21h40m UT on November 18. The normal peak is expected near 09h UT on November 17. Other potential maxima are not excluded. Observing will be difficult because of the bright waning Moon, but is important. The proximity of the shower's parent comet 55P/Tempel-Tuttle helped produce strong to storm returns in 1998-2002. It was at perihelion in 1998. Very swift meteors, often trained.
The α Monocerotids had a suspected periodicity of ten years between their high, short-lived outbursts. The most recent one was in 1995, very well-seen across Europe. Estimated ZHRs were circa 420, but for only about five minutes; the whole outburst took less than half an hour! However, no outburst recurred in 2005, so the periodicity is unproven. Observers need to be alert every year, just in case. Very swift meteors. The maximum is due at 09h25m UT on 2008 November 21, in daylight for the UK, and with a waning crescent Moon anyway.
The Geminids are associated with asteroid 3200 Phaethon, rather than a comet, and their meteoroids seem to be rather denser than those in most meteor showers too. Reliably good rates can be seen for around two nights over their peak, but drop away very quickly after the maximum itself. Medium-speed, often bright, meteors. Their peak is due on 2008 December 13, within 2h20m of 23h UT, ideal for British watchers, but with a full Moon. Rates should be strong enough still to be worth a look under clear skies on December 13-14.
The Ursids are linked with Comet 8P/Tuttle (period around 13.5 years; at perihelion on 2008 January 26). Their peak rates can be quite variable from about 10-50, with especially good activity last in 1986. Medium to slow meteors. Peak: December 22, 07h-10h UT (waning crescent Moon).
The minor Coma Berenicids are poorly-known, and badly need more observing. Very swift meteors. Well-timed peak almost at new Moon.
Antihelion Source
This continuously-active source has a large, diffuse radiant area near the ecliptic, which tracks along slowly, roughly opposite the Sun in the sky, hence its name. Activity from it is never high, and observed rates can be virtually nonexistent for UK watchers when the radiant area is at its most southerly, from May to July. Some near-ecliptic sources are strong enough to stand out from it, such as the SDA, and possibly the CAP, in late July, while the two autumnal Taurid showers are so strong they effectively replace the ANT while they are present. Medium speed meteors, comparable in brightness range to the sporadics. You will need to extrapolate the radiant's centre for dates not listed, or see the radiant drift chart for the current month elsewhere on this website.
