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Dr. Peter Jenniskens
Petrus.M.Jenniskens [at]
Maj. Steve Butow
Stephen.J.Butow [at]

Responsible NASA Official:
Greg Schmidt
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Ames Research Center

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Last Updated:
August 19, 2011

Portrait gallery team members

2011 DRACONIDS: NEXT BIG OUTBURST The 2011 Draconids are expected to peak over Europe at rates of about 200/h in a clear sky on October 8 (600/h high in the mountains): many slow-moving meteors for about an hour centered on 19:57 UT. A bad Moon will hamper observations from the ground, but it should still be an unusual sight. Look away from the Moon. North America will be in daylight so that the shower is not visible from there. Asia will be on the wrong side of the Earth to face the shower. [More here]

2010 LEONIDS: BACK TO NORMAL The leonid storm season has ended, with the next outbursts not predicted until around 2028. That means, for now peak rates will be around 12 an hour in the early morning hours. To see the expected rate from your location, go here, and select the shower "Leonids" and the date of the observation (around Nov 17-18).

2009 Leonids
Region of visibility of the 2009 Leonid outburst [click for larger version]

2009 LEONID OUTBURST FORECAST A significant shower is expected this year when Earth crosses the 1466-dust and 1533-dust ejecta of comet 55P/Tempel-Tuttle. According to J. Vaubaillon, the narrow (about 1-hr) shower is expected to peak on November 17, 2009, at 21:43 (1466) and 21:50 (1533) UT, perhaps 0.5 to 1.0 hour later based on a mis-match in 2008, with rates peaking at about ZHR = 115 + 80 = 195/hr (scaled to rates observed in 2008). E. Lyytinen, M. Maslov, D. Moser, and M. Sato all predict similar activity from both trails, combining to about ZHR = 150 - 300 /hr. P. Jenniskens notes that if the calculated trail pattern is slightly shifted in the same manner as observed before, then the 1533-dust trail would move in Earth's path and its rates would be higher (the 1466-dust trail would move away). However, the 1533-dust trail is distorted in the models, and because of that it is not clear how much higher that would be. This remains a rare opportunity to study old dust trails from comet 55P/Tempel-Tuttle. In such old trails, the model of Lyytinen and Nissinen predicts wide trails, which can be tested by measuring the width of the outburst profile. [Latest updates]

Update Nov. 12: Nepalese astronomer P. Atreya is organizing an international ground-based observing campaign near Kathmandu, Nepal, where he will be joined by P. Jenniskens, J. Vaubaillon, and others. First reports will be posted here.

2007 trails
Two Leonids were captured on 2007 November 18 at 12:56:45-56:55 UT in this all-sky image by Peter Jenniskens from Fremont Peak Observatory, California

2007 LEONIDS, FIRST IMPRESSION A crystal clear night here in N. California resulted in these two Leonids being captured in one image. The bright light in the east is Venus. The Leonid ZHR on Nov. 18 9:30-13:30 UT was measured at 23 +/- 4. The International Meteor Organization reports that rates continued to increase and has reached ZHR ~ 42/hr over Europe in the night of Nov. 18/19. This is stronger than expected for the annual Leonid shower and shows that the Filament component has returned. Sadly, we will not be able to confirm the high rates in N. California, because of overcast skies tonight - Peter Jenniskens.

See also this Taurid meteor of Nov. 18 11:03:54 UT and comet 17P/Holmes. Many of our meteor showers such as the Taurids may have originated in a process of fragmentation similar to that experienced now by 17P/Holmes.

2007 trails
Location of comet Tempel-Tuttle's dust trails at Earth orbit in November 2007 in calculations by Jeremie Vaubaillon (Caltech).

2007 LEONID FORECAST Earth will have an encounter with the 1932-dust trail of comet 55P/Tempel-Tuttle on 2007 November 18 at 23:03 UT, according to Jeremie Vaubaillon (Caltech). Esko Lyytinen of Finland put the peak time earlier at 22:36 UT. Meteors would radiate from R.A. = 154.0 deg., Decl. = +21.4 deg., at geocentric speed of 70.9 km/s, according to I. Sato. The trail encounter is similar to that last year and peak rates are expected to be less, somewhere around ZHR = 30 /hr. The outburst will last only 1-2 hours (FWHM about 0.68 hours, according to Jenniskens 2006). What you can see.

2006 LEONID RESULTS In a paper submitted to Icarus, P. Jenniskens et al. report on the lack of frail meteoroids during the 2006 Leonid shower. For the similar 2007 encounter, they anticipate a peak rate of about ZHR = 32 Leonids/hr and a magnitude distribution index close to 2.6. Full paper [text], [Table], [Figures]

2006 LEONID FORECAST The 2006 Leonids will show a dust trail encounter with the 1932-dust trail of comet 55P/Tempel-Tuttle, as well as the possible return of the Filament component. David Asher's original prediction put the peak time at 04:45 UT on November 19, with a peak rate of about 100 per hour, visible from western Europe and western Africa. Peak time of the Filament component is uncertain. The traditional maximum of the annual Leonid shower is earlier on November 17, around 16:45 UT, well placed for the western USA (early morning of November 18 local time). More information:

2005 LEONID FORECASTING The 2005 Leonids are expected to show only moderate activity this year, with only one possible trail encounter on November 21, at around 01h UT. This encounter was first pointed out by M. Maslov and concerns a very perturbed old trail ejected in A.D. 1167. Rates will be low. Nevertheless, it is important to try to confirm this encounter. More information here.

Trail positions 2004

2004 LEONIDS: FIRST REPORTS First reports indicate elevated Leonid rates on Nov. 18/19. At Fremont Peak Observatory in California, where Mike Koop, Jeremie Vaubaillon and Peter Jenniskens observed, Leonid rates rose to about 20/hr at 11h UT before fog rolled in. Bob Lunsford reports peak rates of 30 and 28/hr from southern California. This is up from the expected 5-10/hr of annual shower activity at that time. We suspect this is the "Filament" component. Leonids were active too in the previous two nights. It is not clear yet if the various predicted dust trail encounters were seen.

2004: TOUCHING ON THREE DUST TRAILS NOVEMBER 8 + 19 The latest news is a possible dust trail encounter from dust ejected in 1001, expected to peak at 23:30 UT Nov. 8. More information here. For November 19, Jeremie Vaubaillon, Esko Lyytinen, Markku Nissinen, and David Asher have arrived at a common prediction for this year's 2004 Leonids. It was found that Earth will pass close to two dust trails, those of 1333 and 1733. Any outburst from the 1333 trail will peak at 06:42 UT, November 19, well positioned for U.S.A. observers. Rates will not be high, ZHR = 10 at best. The second 1733 trail will arrive at 21:49 UT, when the rates can go up as high as ZHR = 65. That outburst is best seen in Asia. Even though rates will not be as high as in past Leonid storms, it is important to continue observe these showers to learn how dust is distributed by the parent comet 55P/Tempel-Tuttle. More information here.

CHANDRA HIT BY LEONID? The Chandra X-Ray observatory reports a hit by a meteoroid on November 15, 2003. More here.

2002 LEONID ORBITS MEASURED Josep Trigo-Rodriguez and colleagues present ten meteoroid orbits from the 1767 dust trail in a recent issue of Icarus (171, p. 219), based on results from the Leonid MAC supporting ground-based campaign in eastern Spain. There is good agreement between theoretical orbits from the 1767 ejecta of 55P/Tempel-Tuttle and the observed meteoroid orbits.

FIRST RESULTS 2003 LEONIDS The first reports on the 2003 Leonid shower are posted here. The 1499 dust trail (about 17h UT on Nov 13) was apparently confirmed by Japanese visual observers, albeit not as intense as predicted by Esko Lyytinen. A broad peak (the "Filament") with ZHR about 50 was observed around November 19, as predicted by Peter Jenniskens. Other minor trails at 7h UT (1533) and 17h UT (1733) could not (yet) be confirmed due to lack of data. Clouds interfered with many observing plans.

LATEST ON PROSPECTS FOR 2003 LEONIDS This year's Leonids will not see a repeat of the storms of past years. That said, there are two outbursts predicted that offer exciting opportunities for viewing. Esko Lyytinen predicts that on November 13 (~ 16h UT), Earth will cross the dust trail ejected in 1499, six days prior to the main maximum! Peter Jenniskens and Hans Betlem predict that on November 19, there will be a broad Perseid-like shower of bright Leonid meteors lasting about a day. Jeremie Vaubaillon points out that at 07:27 UT that day an old dust trail from 1533 will be near Earth orbit. Overview of expected activity.

Further Leonid news items

LEONID MAC mission news

1999 Leonid storm
The 1999 Leonid storm from 39,000 ft.

FLUX ESTIMATOR UPDATE Dec. 2007 - It is now possible to calculate the shower activity from your local observing site for all established meteor showers in the IAU List of Established Showers. The number in front of each stream is the official IAU shower number. Go to: Fluxtimator applet.

GULFSTREAM V METEOR SHOWER MISSIONS In 2007, the Leonid storm research was expanded to target other showers in a series of airborne campaigns that deployed privately owned Gulfstream V aircraft from NASA Ames Research Center:

[Overview of missions]

REPORT OF LEONID MAC MISSION RESULTS book Cambridge University Press has published a 790 page book "Meteor Showers and their Parent Comets" by Leonid MAC principal investigator Dr. Peter Jenniskens. The book contains meteor outburst predictions for the next 50 years and much new information about the association of meteor showers with newly discovered Near Earth Objects. It is an academic overview of the field of meteor astronomy, the first since Lovell's 1954 book "Meteor Astronomy", but written so that it can be used by both amateur and professional astronomers interested in chasing meteor outbursts.

2003 + 2006 LEONID OBSERVING CAMPAIGNS Now the storms are over, there will be no more Leonid MAC missions. A number of potential smaller meteor outbursts are predicted for the years 2003 - 2007. Each encounter will shed more light on the distribution of dust in the trails, especially in old trails and those parts of trails caused by grains ejected with large initial ejection speed or those experiencing unusually high radiation pressure. We work to organize ground-based observing campaigns to provide ground truth for the further development of dust trail models.

  • 2006: Ground-based observations planned for Spain. Observations executed under clear sky conditions.
  • 2003: Ground-based observations at Fairbanks, Alaska. High framerate images of Leonids in days before the peak. Peak clouded out.

group photo
Group photo of 2003 Leonid MAC Workshop participants

2003 LEONID MAC WORKSHOP On August 28-30, participating researchers and other workers in the field compared notes on the 2002 Leonid storms at the 2003 Leonid MAC Workshop at NASA Ames Research Center (CA). The "shock" in meteor images has been confirmed. The organic signature reported during the 1999 mission in infrared spectra is confirmed. There turns out to be a large diversity in comet meteoroid composition and morphology. New molecules have been detected in meteor emissions, and there is now an answer to the long standing mystery of persistent trains. A report with much more news will follow.

Group photo DC8 team

2002: NASA/DC-8 Airborne Laboratory crew and scientists.

Group photo FISTA team

2002: USAF/FISTA crew and scientists.
(photos courtesy Eric James, code JIT, NASA Ames).

2002 LEONID MAC CAMPAIGN REPORTS AND IMAGES The NASA and USAF sponsored 2002 Leonid MAC mission was a great success. Both aircraft were above clouds and under perfect conditions for viewing both of the 2002 Leonid storms enroute from Torrejon, Spain, to Offutt AFB near Omaha, Nebraska. All instruments worked as expected and aurora, moon, and meteors made the view scenic and truely spectacular at times.

2002 zhr

2002 Leonid flux measurements from the air (top) and ground (bottom).

First reports can be found here:

Astrobiology SPECIAL LEONID MAC ISSUE OF JOURNAL ASTROBIOLOGY The journal Astrobiology has changed its traditional front cover to feature one of the spectacular fireballs photographed during the 2001 Leonid shower. This one by Kris Asla from Aloha, Oregon. The publisher, Mary Ann Liebert Inc., agreed to the change after this picture was submitted as possible cover art to go with a series of five papers, presenting results from the 2001 and 2002 Leonid MAC missions: studies of the plasma temperature and temperature decay in the wake of meteors and studies of CN, OH, and H emission that probe the exogenous delivery of organics and water.

Further Leonid MAC news items

meteor airborne science live airborne Jesus Frias Rick Rairden Ian Murray Jiri Borovicka Hans Nielsen Peter Jenniskens Steve Butow Hajime Yano Toshihiro Kasuga Shinsuke Abe Armin Kleinboehl Klaus Kuenzi Joe Kristl Tom Hudson Sandy Nierman Mike Taylor John Plane bios page bios page Bill Smith Kristina Smith Ray Russell George Rossano David Lynch David Nugent Mike Koop Jane Houston Ruediger Jehn Morris Jones Chris Crawford David Holman Emily Schaller Peter Gural Pavel Spurny Detlef Koschny Melissa Pfeffer