NAMN Notes is a monthly newsletter produced by the North American Meteor Network and is available both via email and on the NAMN website at: http://www.namnmeteors.org
1. Leonids - Moonlight but Monitor...
2. Taurids - Watch for Fireballs...
3. Alpha Monocerotids - 10 Year Periodicity?...
4. Other November Activity...
5. Upcoming Meetings...
6. For more info...
The Leonids (LEO) have been a source of intense interest these past number of years, but are expected to have only moderate activity this year - and will be hampered by severe moonlit conditions as well.
The shower peaks on November 17th at about 14h30m UT, according to the IMO, the International Meteor Organization, in their 2005 Meteor Shower Calendar. The duration of the shower is from about November 14th to 21st. These are fast meteors, at about 71 km per second.
ZHR rates are listed as 20+ meteors per hour. What is ZHR? This is Zenithal Hourly Rate, and is the number of meteors that an observer would expect to see, on the average, in an hour, if they are out observing under dark country skies, and if the radiant, the area in the sky where the meteors seem to come from, is directly overhead. However, we will not have dark skies, even in the country this year, as the peak occurs just a day past full moon. However, try to put the moon behind you when observing, or block it with a tree or whatever you have handy, and your eyes will be better able to detect the meteors. Some observers have even used black umbrellas to block moonlight.
A map of the Leonid radiant can be found on the IMO website at http://www.imo.net/calendar/2004/fall
Although we are past the years with strong activity, please monitor this shower. Even small surprises can occur - and will reward the active observers!
The 2005 predictions by Mikhail Maslov of Russia include the following activity due to encounters with old debris trails, from his website at http://feraj.narod.ru/Radiants/Predictions/Leonids2005eng.html:
From the debris trail ZHR formed in the year: meteors/hr date / time (UT) 1001 2 Nov 10 / 8:30 1333 1 Nov 19 / 1:28 1167 1 Nov 20 / 22:47 1167 6 Nov 21 / 0:14 1167 9 Nov 21 / 1:43 1167 2 Nov 21 / 3:22
The article on his website is interesting reading - check it out. He also provides some very interesting graphs, including one showing the expected meteor rate by date throughout November, with the additional activity rate superimposed.
To read any last minute comments on Leonid activity, we suggest you join our MeteorObs discussion group. Our online 'subscribe' form can be found at http://www.meteorobs.org/subscribe.html. You can use this simple form to subscribe - or unsubscribe - at any time. By signing on, you will be able to read the discussions - and hear about the meteor observations around the globe, as they are reported. Questions from new observers are also always welcome.
If you want to record data on this shower for the meteor researchers, check out our NAMN Observing Guide for information on what to record. Our Guide can be found at http://www.namnmeteors.org/guide.html. We record such info as the time a meteor occurred, its magnitude (brightness), the shower it belongs to, its speed, and other comments such as train left behind, or color. General information to record includes such things as how dark your perceived sky is (limiting magnitude), and comments on weather and cloud cover. If you have any questions, drop a note to our NAMN Coordinator at meteors@comcast.net
NAMN has some good star charts to mark your radiants on before you go out observing. These charts also show constellations for the whole sky, and give the brightness of a number of stars to use in judging the magnitude of the meteors you see. Our 4 printable charts can be found at http://www.namnmeteors.org/charts.html. Set your printer to 'landscape' mode.
Forms to record your observations can be found at http://www.namnmeteors.org/namn_form.html and http://www.namnmeteors.org/appendixC.html
The Taurids could well be the highlight of the November skies. The southern Taurids (STA) peak on November 5th, and the northern Taurids on November 12th, with peak rates lasting a number of days. Both showers can be observed through until about November 25th. The normal ZHR rate for each is about 5 meteors per hour at the peak.
However, these meteor showers are part of the complex of showers associated with Comet 2P/Encke - and could provide some surprises this year. The IMO refers to 2005 being a 'potential Taurid Complex meteoroid 'swarm' return year'. In their 2005 Meteor Shower Calendar they comment further:
"David Asher has indicated that increased Taurid fireball rates may result from a "swarm" of larger particles within the Taurid stream complex, and he suggested such "swarm" returns might happen in 1995 and 1998 most recently. In 1995, an impressive crop of bright Taurids occurred between late October to mid November, while in 1998, Taurid ZHRs reached levels comparable to the usual maximum rates in late October, together with an increased flux of brighter Taurids generally. This year brings the next potential October-November "swarm" return. Thus, observing what happens with the Taurids between last quarter Moon in October through to the Northern Taurid maximum in November is most important..."
"The activity of both streams produces an apparently plateau-like maximum for about ten days in early November, and the showers have a reputation for producing some excellently bright fireballs at times..."
Both showers have almost slow meteors - the southern at about 27 km per second, and the northern at about 29 km per second. A map showing these two meteor shower radiants, and their movement throughout November, can be found at http://www.imo.net/calendar/2005/fall
Observations are strongly encouraged throughout November, in order to detect surprises these Taurid showers may provide!
The alpha Monocerotids (AMO) peak on November 21st at about 15h00m UT, but can be seen from about November 15th to 25th. These are fast meteors, with a velocity of about 65 km per second.
The ZHR rate for this shower is listed as 'variable', but is usually about 5 meteors per hour. This 'variable' factor indicates that the shower should always be monitored closely each year for surprises!
The alpha Monocerotids may have a 10-year periodicity. Enhanced activity was observed in 1925, 1935, and 1985. The last outburst was in 1995, and was seen by many observers across Europe. The maximum rate in 1995 was about 420 meteors/hour but this lasted for only about 5 minutes, with the entire outburst duration about 30 minutes.
A map of the radiant can be found at http://www.imo.net/calendar/2004/fall
If you have clear skies during this shower, please record your observations for the meteor researchers!
The Orionids (ORI), debris from Halley's Comet, although having peaked on October 21st, can still be observed through until about November 7th. These are fast meteors, at about 66 km per second. ZHR rates at the peak were about 23 meteors per hour, but rates in November will be much lower. Photos of the comet can be found on Gary Kronk's website at http://cometography.com/pcomets/001p.html and a map showing the radiant of the meteor shower can be found on the IMO website at http://www.imo.net/calendar/2004/fall
The chi Orionids (XOR), although not reaching a maximum until December 2nd, can be seen starting about November 26th. These are almost slow meteors, with a velocity of about 28 km per second. ZHR rates at the maximum will be about 3 meteors per hour, but rates in November will be low. A map showing the radiant position can be found in the IMO Calendar at http://www.imo.net/calendar/2002
The December Phoenicids (PHO), although not peaking until December 6th, can be observed starting about November 28th. This is a southern shower, with the radiant at -53 degrees, but is included for those observers in southern latitudes. These are very slow meteors, at about 18 km per second. The ZHR rate is listed as 'variable', which means observers should always monitor the shower for unexpected activity. Back in 1956, rates did reach about 100 meteors per hour at the peak. A map of the radiant can be found at http://www.imo.net/calendar/2004/fall
Lastly, the Monocerotids (MON) start to become active about November 27th, although the peak will not occur until about December 9th. These are average velocity meteors at about 42 km per second. ZHR rates at the peak will be about 3 meteors per hour, and rates in November low. To see where the meteors will come from, check out the map at http://www.imo.net/calendar/2005/fall
For other minor showers not on the IMO, the International Meteor Organization, 'Working List of Visual Meteor Showers', check out the very informative website 'Comets and Meteor Showers' by Gary Kronk at http://comets.amsmeteors.org. It gives further details on more obscure showers, and a wealth of observational and historical detail on all the major and minor showers.
Besides November's main activity, and other minor showers, there is also sporadic meteor activity. This sporadic meteor activity is about 7 meteors per hour, visible to the unaided eye. Some of these are random, and some belong to old untraceable meteor showers.
Planets at midmonth, and their magnitudes, for northern observers, are:
Venus -4.3 low in southwest in evening twilight Mars -2.2 in Aries Saturn 0.3 in CancerFor a sky chart showing the positions of all the planets visible this month, go to http://www.heavens-above.com, select your country, then your city, and go to 'Whole Sky Chart'.
The phases of the moon for November are as follows:
Wed. Nov. 2 new moon Wed. Nov. 9 first quarter Wed. Nov. 16 full moon Wed. Nov. 23 last quarterFor a great printout of moon phases for the month, check out http://stardate.org/nightsky/moon
June 8-14, 2006, Ostersund, Sweden...
The Workshop on Impact Craters as Indicators for Planetary Environmental
Evolution and Astrobiology will be held in Ostersund, Sweden. Sessions
include terrestrial craters, craters on other planetary bodies, the
influences of the impact on the target area, the target area on the fate of
the projectile, and the properties of the impactor on the cratering process,
other consequences (eg. tsunamis), environments created by the impact and
their importance for life, and astrobiological aspects of impact cratering.
There will be two study field trips to the Lockne Crater, and an excursion
to the GeoCenter-Lockne Impact Crater Museum. For information, check out
the website at http://www.geo.su.se/Lockne2006
and contact Dr. Jens Ormo of
the Planetary Geology Laboratory, CSIC/INTA, Madrid, Spain at ormo@inta.es
For information on upcoming astronomy meetings, see: "International Astronomy Meetings List" at http://cadcwww.hia.nrc.ca/meetings
NAMN email: namn@namnmeteors.org
NAMN website: http://www.namnmeteors.org
Mark Davis, meteors@comcast.net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network
Cathy Hall, chall@cyberus.ca
Ottawa, Ontario, Canada
Writer, NAMN Notes
Lew Gramer, dedalus@alum.mit.edu
Homestead, Florida, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'
Kevin Kilkenny,
namnfireball@earthlink.net
Staten Island, New York, USA
Coordinator, Fireballs and Meteorites
Back issues of NAMN Notes can be found on-line at the NAMN website
and in the MeteorObs archives at:
http://www.meteorobs.org
by selecting 'Browse Archive by Month'
To subscribe to the meteor email list or
to find out information on our weekly chat sessions:
Contact Lew Gramer at:
dedalus@alum.mit.edu