 1. Outburst alert2. Dutch clouded out3. International observations4. Comet 7P/Pons-Winnecke5. IMO Shower Circular |
Casper ter Kuile This page presents an overview on the June Bootid Outburst of June 1998, 27/28 Updated: July 7, 1998 |
Abstract
Casper ter Kuile
This page presents an overview on the
June Bootid Outburst of
June 1998, 27/28
Updated: July 7, 1998
1. IAU-C22 PRO-AMAT WORKING GROUP CIRCULAR
OUTBURST ALERT - JUNE 27/28 A meteor outburst was first detected by Japanese observers on 9h UT June 27th, from an increase of meteor rates by radio-foreward meteor scatter signals (K. Suzuki, M. Ueda: 3-5 times above normal rates), with confirmation from visual observers. Raw rates of up to 50 meteors/hr were observed in the early evening (indirect reports via M. Takanashi and M. Koseki - NMS). Italian observers Roberto Haver, Enrico Stomeo and Roberto Gorelli (UAI- Sezione Meteore) observed the same outburst between 21:20 June 27 and 01:30 UT June 28, with Zenith Hourly Rates above 100. The shower was also reported from Portugal, where astronomer Derek Penn counted 27 outburst meteors in 15 minutes. The sighting is confirmed from California, where observers noticed the meteors on June 28 around 5h UT. This shower ** may still be detectable ** in the night of June 28/29 and later and further observations should be attempted by both professional and amateur observers. Of special interest is any low-level activity that continues for some time. Please inform the usual channels of your observations. The radiant has been placed near RA=224o, DEC=+50o by the Italian observers and others agree with this general location. The shower is visible throughout the night, and highest in the early evening hours. The Moon will be hardly interfering, except perhaps in the first hour(s) of the night. Radiant and time of year suggest that this is another manifestation of the June Bootids, which were detected by W.F. Denning in 1916. However, that event has been associated with comet 7P/Pons-Winnecke and the comet now has a decending node at 1.26 AU from the Sun, while the minimum distance between Earth and comet orbit during passage of the orbital plane is on June 25.15 (UT) at 0.244 AU. An unlikely large distance for meteor outburst activity, as was pointed out by Peter Bus (DMS). An alert has gone out also on IAU Circular 6954 (June 27). The following have expressed an interest in any information on this event (please inform us if this list be extended): E. Stomeo, Unione Astrofili Italiani - Sezione Meteore (stom@iol.it) CP 654 - Venezia 30100, Italy P. Jenniskens/NASA-ARC (peter@max.arc.nasa.gov) Mail Stop 239-4 Moffett Field, CA 94035-1000, USA Peter Jenniskens President IAU C-22 Pro-Amat Working Group .......................................................................... Peter Jenniskens The SETI Institute e-mail: peter@max.arc.nasa.gov NASA Ames Research Center tel: (650) 604-3086 Mail Stop 239-4 fax: (650) 604-1088 Moffett Field, CA 94035-1000 http://www-space.arc.nasa.gov/~leonid/
2. June 27/28 Bootid Outburst: Dutch clouded out...
Dutch clouded out :-( Hello, Shit; we have been clouded out on both nights 27/28 and 28/29. 27/28 saw heavy rain. the afternoon of june 28 was very clear however, raising prospects and excitement after the messages on the iota Draconid/june Bootid outburst came in (Mr. Koseki and Enrique: many thanks for the quick reporting! That was really appreciated!). But in the late afternoon clouds entered from the North Sea. Last night june 28/29, Robert Haas and I have been out on the Road from 23h to 3h local time, trying to find clear weather, driving from Leiden to Amsterdam, from Amsterdam into the Flevo-polders to Dronten, then into the Veluwe, via Ermelo, Putten to Arnhem (the famous city in which the 'Bridge too far' is located), and then back again. Allas, all our efforts were only rewarded with a few glimpses of stars in keyhole-size clearings and finally massive clouds and lightning. Well, we have tried to the best of our possibilities buth weather just not cooperates at the moment. - Marco Langbroek Dutch Meteor Society, the Netherlands
Subject: june Bootids 1995-1997 Dear all, With respect to the june Bootid (or 'iota Draconid'/ june-Draconid) outburst of last weekend, it is perhaps usefull to report that Dutch observers have noted a possible very low level activity of this stream in the period 1995-1997. Koen Miskotte and I started to classify this stream in 1995, because it appeared in Peter Jenniskens' outburst catalogue (A&A 295 (1995), 206). The observations of stream members reported below have been abstracted from narrative observational reports by Koen and me in Radiant (journ. DMS) vols. 17 (1995) p. 71-73; and vol. 19 (1997) p. 99-102; this log is >notgood, reliable<1998 radiant position are possible. All obs. intervals below are roughly centered at 0h UT by the way. obs. date iDra Lm Teff Langbroek 26/27-06-1995 1 6.1 1.97 Miskotte 27/28-06-1995 1 6.5 2.02 Miskotte 28/29-06-1995 1 6.1 1.92 Langbroek 28/29-06-1997 1 6.1 2.00 Langbroek 5/6-07-1997 1 6.5 1.00 It concerns very slow distinctive meteors from a radiant near RA 230, dec. +55, with radiant diameter taken in classifying (by Langbroek) approx. 15 degrees. The data point to the possibility of a very low level annual activity over several days with ZHR very low, <2. Please note that with such low rates sporadic line-ups can occur! Since the meteors are distinctive slow however, it would surprise me if all the specimens reported above were in reality sporadics however. More info follows when Koen finished checking the archive. Marco Langbroek Dutch meteor Society (DMS) Team "Delphinus"
A short summary of observed june-Bootids between 1977 and 1997: Year: Time(UT): Boo: total: LM: 28/29 06 1979 21:50 - 23:00 1 6 4.8 29/30 06 1986 22:05 - 23:20 1 11 5.5 30 06/01 07 1986 22:15 - 23:30 - 12 5.6 29/30 06 1989 22:15 - 23:00 - 8 5.8 Best wishes, Carl ---------------------------------------------- C.F. Johannink Schiefestrasse 36 48599 Gronau Germany Phone: + 49 2562 22345 Email: cjohannink@netside.de -----------------------------------------------
3. June 27/28 Bootid Outburst: International observations
Subject: Possible Pons-Winneckids(June Bootids)? Unusual meteor rates shocked Japanese observers. Evening of June 27 FM radio observer, K.Suzuki posted Japanese mailing list that he recorded three times larger rates than usual (preceding nights) from 18LT(=JST, 9UT). M.Ueda followed close behind. He wrote not three times but five times!, and continues now 23LT. National Astronomical Observatory informed us some visual witnesses arrived and suggested meteor rates was over one hundred. M.Takanashi cites from other source that one can see more than 50 meteors per hour inside from astronomical dome! Y.Yabu sends report that shows this meteor shower includes fireballs. Many visual reports suggest that the radiant point locates near boundary of Ursa Major and Bootes. The position and the date strongly suggest it is Pons- Winneckids! Very unfortunately, Japanese veteran visual observers were obstructed by clouds because it is the most rainy season in Japan. No velocity data was reported and we have not been possible to confirm it was really from the comet Pons-Winnecke by now. It will follow more details from some others concerning this special meteor show! Masahiro Koseki(The Nippon Meteor Society)
Hi Bob, Mark and others!
Tried to send my post to meteorobs but it's off line right
now. Every message gets bounced back.
Bev Ewen-Smith, coaa@mail.telepac.pt wrote: (from imo-news@imo.net)
>Saturday night 1998 June 27. 21:30 - 00:30
>
>We were doing routine observations under a clear dark sky and
>became aware of a high level of meteor activity. One of the astronomers
>(Derek Penn) spent half an hour counting (single observer, limited field
>of view due trees) and counted 27 in fifteen minutes. There were so many
>(and many bright ones) that there were frequently two at once (or seemed
>so).
>The frequency made it a simple matter to identify the radiant as being
>at the top end of Bootes (furthest from Arcturus) or perhaps a tiny bit
>on the Corona B side or the eta-Uma side of that point. Certainly, they
>far, far outnumbered sporadics, if that gives a measure. The level began
>high as soon as it got dark and was still performing splendidly when we
>packed
>up a little after 1 am local time.
>
>Unfortunately, nobody had the wit to suggest photographing the area of the
>radiant to clinch it. Perhaps we'll try again tonight if it's still going.
>
>Certainly a very fine display indeed and at least comparable to the special
>Perseids of a few years ago.
>
>Bev
I set up for a meteor watch from my backyard last night. Unfortunately,
a storm system passed over the region and scattered clouds remained the
rest of the night. This prevented me from doing a standard meteor report,
but I still watched through 40-80% clouds just in case I'd see something.
Between 1:30-2:30 local EDT, I noted one slow but trained, average
magnitude meteor in the north apparently coming from the top end of
Bootes. 2 sporadics and one possible member of the Sagittarids
complexe. No unusual activity to report here.
Pons-Winneckids (June Bootids) appear to be a very similar shower to
the October Draconids. Both seem to produce a usually very short and
barely detectable peak, but at rare occasions may become very
spectacular. Also of note is that both parent comet each have a
short period orbit of about 6 years.
Could it be perhaps still possible to see the remaining effects of
this meteor outburst tonight ? I will be certainly keeping an eye
on the sky tonight just in case before the weather completely
deteriorates again.
What is going on ? Is this a freak meteor outburst completely
unpredictable ? I'm not aware of the parent comet being very close
to earth right now. I thought Pons-Winneckids would likely never
again burst since they last displayed in 1927.
Pierre
Pierre Martin . . .
******************************************* / / . . * .
Ottawa, Ontario, CAN / / . . . . .
Visual meteor observer // / / . . . .
Ottawa Astro Observers Group / / . * . .
Graphic Designer (National Aviation Museum) =/ / |\ . . .
******************************************* / | \ . | . .
/ | \ | \ .
/ | \ * . \
/ | \ \
| *
Subject: Re: Dutch clouded out :-( Marco, We were clouded out along the immediate Pacific Coast plus the timing was bad as I had to be at work by 2am the next morning. Had this happened one day later I may have caught a glimpse of it as it was clear Sunday night/Monday morning. A casual watch for one hour just after sunset revealed no activity. I also watched from 1130pm-to 430am and saw 1 possible member. Bob Lunsford
From: tpcoope@mweb.co.za Subject: June Bootids I was happy to see all the reports of the June Bootid outburst. The event was witnessed by several observers in South Africa too on the evening of June 27. This included 4 fireball reports I received so far. As for me, I missed the outburst, due to observing an occultation of a star by minor planet 248 Lameia. I saw a long pathed June Bootid while waiting for my eyes to dark adapt, then commenced a 20 minute watch of the magnitude 7.8 star. Happily we witnessed the occultation, and five of us obtained good chords across the minor planet, including a six second disappearance in my case. As a result we will be able to derive a very accurate diameter of the minor planet from the timings. Needless to say, I'm disappointed at not witnessing the meteor outburst first hand, but we are over the moon with the occultation results. Bye for now Tim Coope
Subject: Re: Dutch clouded out :-(
Hello Marco,
California was clear! We had a very nice night starting at about 5h:30m UT
and continued observing until 9h30m UT. Not a single meteor was with
certainty identified as a Bootid from the Mercey site observations. FPO is
not in yet. We ran video and photography and perhaps those records bear
some withness. However, in all respects the shower was over by June 29 5h UT.
The night before, the shower was spotted in the beginning of the night
by Chris, Terry and Sandra independently. No formal observations were made
that night, unfortunately.
-Peter
..........................................................................
Peter Jenniskens
The SETI Institute e-mail: peter@max.arc.nasa.gov
NASA Ames Research Center tel: (650) 604-3086
Mail Stop 239-4 fax: (650) 604-1088
Moffett Field, CA 94035-1000
http://www-space.arc.nasa.gov/~leonid/
Preliminary observational data collected by members of Unione Astrofili Italiani - Sezione Meteore (UAI-sm): Code Observer ---------------------- GORRO Gorelli Roberto HAVRO Haver Roberto STOEN Stomeo Enrico Loc Site Lat Long --------------------------------- 1 Alberoni, VE 45,36 -12,33 2 Frasso Sabino, RI 42,23 -12,81 Loc Obs Jun98 UT Dur Lm Cf TOT BOO Other ------------------------------------------------------------ 2 GORRO 27,899 2120-2150 0,50 5,6 1,00 17 15 2 2 GORRO 27,920 2150-2220 0,50 5,6 1,00 16 16 0 2 GORRO 27,941 2220-2250 0,50 5,6 1,00 14 13 1 2 GORRO 27,962 2250-2320 0,50 5,6 1,00 11 10 1 2 GORRO 27,983 2320-2350 0,50 5,6 1,00 12 8 4 2 GORRO 28,003 2350-0020 0,50 5,6 1,00 15 8 7 2 GORRO 28,031 0030-0100 0,50 5,6 1,00 14 7 7 2 GORRO 28,052 0100-0130 0,50 5,6 1,00 9 4 5 Bootid radiant 240°/+50°, about 15°diameter. tm= 30sec Loc Obs Jun98 UT Dur Lm Cf TOT BOO Other ------------------------------------------------------------ 2 HAVRO 27,899 2120-2150 0,50 6,0 1,00 18 14 4 2 HAVRO 27,920 2150-2220 0,50 6,0 1,00 18 17 1 2 HAVRO 27,941 2220-2250 0,50 6,0 1,00 19 17 2 2 HAVRO 27,962 2250-2320 0,50 6,0 1,00 14 11 3 2 HAVRO 27,983 2320-2350 0,50 6,0 1,00 13 10 3 2 HAVRO 28,003 2350-0020 0,50 6,0 1,00 14 8 6 2 HAVRO 28,031 0030-0100 0,50 6,0 1,00 14 7 7 2 HAVRO 28,052 0100-0130 0,50 6,0 1,00 12 4 8 Bootid radiant 224°/+50°; 9% with trail. tm= 40sec Loc Obs Jun98 UT Dur Lm Cf TOT BOO Other ------------------------------------------------------------ 1 STOEN 27,891 2110-2135 0,42 5,2 1,10 5 3 2 1 STOEN 27,908 2135-2200 0,42 5,2 1,10 4 3 1 Bootid radiant (1950) 220°/+59° very diffuse. tm= 20sec Obs stream -03 -02 -01 +00 +01 +02 +03 +04 +05 -------------------------------------------------------- GORRO BOO 1.0 1.0 2.0 10 10.5 17.5 25.5 13.0 0.0 GORRO Other 0.0 0.0 0.0 4.5 4.5 4.5 9.5 4.0 0.0 HAVRO BOO 0.0 0.5 2.0 9.5 11.5 10.0 16.0 21.0 17.5 HAVRO Other 0.0 0.0 2.0 2.0 2.0 8.0 2.0 12.0 6.0 STOEN BOO 0.0 0.0 1.0 0.0 0.0 2.0 3.0 0.0 0.0 STOEN Other 0.0 0.0 0.0 0.0 0.0 0.0 1.5 1.5 0.0 # Enrico S t o m e o CP 654 - Venezia 30100 (I) Email: stom@iol.it - stom@unive.it ------------------------------------------- Unione Astrofili Italiani - Sezione Meteore http://astrolink.mclink.it/uai/sez_met
4. The outburst on 1998 June 27 and Comet 7P/Pons-Winnecke (DMS, Peter Bus)
Summary
A brief overview is given for a couple of radiant positions of the June Bootids/Draconids in relationship with the 1998 June 27 outburst.
Also results are given for the distance between the orbit of comet 7P/Pons-Winnecke and the Earth and the shift of the comet's longitude of ascending node.
Because the large distance of 0.244 AU between the orbit of the comet and the Earth the relationship between the outburst and the comet is still questionable.Figure 1
Different radiant positions for the period June 14 to July 19 observed in the period between 1872 and 1998. The square marks the position of the 1916 outburst and the dot the preliminary position for the 1998 outburst. According to different observers between 1872 and 1995, the radiant positions given are the mean position of a large diffuse radiant 5 - 15 degrees in diameter.
Figure 2
The distance between the orbits of comet 7P/Pons-Winnecke and Earth between discovery of the comet in 1819 and the last perihelion passage in 1996. Perturbations mainly coursed by Jupiter have steadily increased the perihelion distance. Therefore the orbit have shifted gradually from inside to the outside of the Earth's orbit.
Since 1921 the comet's orbit is outside of the Earth's orbit.
Figure 3
The shift of comet 7P/Pons-Winnecke's longitude of ascending node between 1819 and 1996. Between 1819 and 1869 the Earth crossed the orbit-plane of the comet on July 16. Between 1898 and 1915 on July 2 and between 1951 and 1996 on June 24 or 25.
Literature:
- Jenniskens, P., Astron.Astrophys. 295-235 (1995)
- Jenniskens, P., IAU-C22 Pro-Amat Working Group Circular (June 28, 1998)
- Kronk, G.W., Meteor Showers, 1988
- Marsden B.G. & G.V.Williams, Catalogue of Cometary Orbits, 9th ed. (1994)
- Nakano, S., in 1996 Comet Handbook, ed. S.Nakano & D.W.E.Green (1995)
5. IMO Shower Circular: June Bootids 1998
------------------------------------- I M O S h o w e r C i r c u l a r ------------------------------------- JUNE BOOTIDS 1998 The first records of this meteor shower with irregular occurrence are from 1916 when W.F. Denning and a few anonymous observers saw an outburst of meteors from a radiant in Draco. Since then activity was very low except for possible significant events in 1921 and 1927. Because of the uncertain radaint position, the shower is often referred to as the June Draconids or iota-Draconids. An outburst of activity similar to the 1916 event was observed by amateurs from all over the world in the night of June 26-27 (western longitudes) and June 27-28 (eastern longitudes), 1998. Just as in the comments of Denning, the activity is reported to be of fairly constant behaviour, in stead of exhibiting a sharp peak. The radiant positions given by the observers scatter strongly. Most of the reports note a 'very diffuse radiant', just like Denning's comments about a large radiation area. According to the most reliable positions derived from the plots of experienced meteor observers, we adopted an average radiant position at alpha:230 deg, delta:+49 deg. The following observers contributed to the below ZHR graph, several occasional observers additionally reported their impressions of the event, giving e.g. radiant positions. CRIST Stefano Crivello (Italy) GORRO Roberto Gorelli (Italy) HAVRO Roberto Haver (Italy) HASTA Hashimoto Takema (Japan) IZUKI Izumi Kiyoshi (Japan) JENPE Peter Jenniskens (USA) KACJA Javor Kac (Slovenia) KERKH Kerr Kathryn (Australia) KNOAN Andre Knoefel (Germany) KREKE Kevin Kretsch (Ireland) NOSKU Kunio Nose (Japan) (video observation) OSAKA Osada Kazuhiro (Japan) RASLI Lina Rashkova (Bulgaria) RENJU Jurgen Rendtel (Germany) SATKO Koetsu Sato (Japan) STOEN Enrico Stomeo (Italy) TAYMA Mark Taylor (USA) TRIJO Josep M. Trigo (Spain) VELVA Valentin Velkov (Bulgaria) Additionally: P. Brown (radar), G. Carstairs, B. Ewen-Smith, D. Girling, V. Grigore, W.K. Hocking (radar), H.G. Konig, A. Marsh, A. Negoescu, D. Penn, L.R. Sobkoviak, P. Suetterlin, K. Suzuki (radio), B. Vanderwark, R. Vodicka ---------------------------------- Date UT Sollon #Obs ZHR +- ---------------------------------- 06/26 2310 95.16 2 16 +-10 06/27 0730 95.464 1 11 +- 3 06/27 1020 95.603 1 90 +-20 06/27 1150 95.662 1 85 +-17 06/27 1930 95.983 3 86 +-68 06/27 2010 95.993 6 62 +-51 06/27 2040 96.014 6 56 +-32 06/27 2120 96.036 8 59 +-32 06/27 2150 96.056 14 46 +-23 06/27 2210 96.072 11 44 +-20 06/27 2240 96.093 14 55 +-24 06/27 2320 96.122 14 48 +-28 06/28 0000 96.144 14 45 +-25 06/28 0040 96.167 10 47 +-25 06/28 0100 96.187 6 35 +-14 06/28 0120 96.199 2 21 +- 4 06/28 1220 96.64 1 0 (video) 06/29 1100 97.53 6 2 +- 2 06/29 2100 97.93 1 0 ---------------------------------- The ZHR is calculated with an average radiant position at alpha:230 deg, delta:+49 deg and a population index of r:2.0. The activity profile has no signs of a sharp peak. Highest ZHRs were observed between 1000 and 2000 UT on June 27, from Australia, Japan and Bulgaria (solar longitude 95.6 degres to 96.0 degrees; eq. 2000.0). The broad activity profile was also noted by Denning in 1916. Individual radiant positions are given below: Plotted meteors: ---------------- GORRO 240 +50 (15deg diameter) HAVRO 224 +50 HASTA 229 +50 OSAKA 221 +51 STOEN 220 +59 (diffuse) Bulg. 231 +44 (VELVA, RASLI, two centers) 234 +48 Radar observation: ------------------ Brown & Hocking 228 +54 (both +-3 deg, quite diffuse) Counted meteors: ---------------- Australia (G. Carstairs, D. Girling, A. Marsh, R. Vodicka) 218 +53 (after zenithal-attraction corr.) CRIST 234 +51 (diffuse) EWEBE 225 +40 (Bev Ewen-Smith) GRIVA 224 +49 KACJA 225 +45 KREKE 255 +55 TAYMA 240 +46 Radiants observed by Denning in 1916 ------------------------------------ Denning 231 +54 (main) Denning 223 +41 (one of secondary) (from Mon. Not. Roy. Astron. Soc. 76, p. 740 and Nature 97, p. 388) NOTE that most of the radiant positions are not corrected for zenithal attraction which can amount to everal degrees according to the extremely low geocentric velocity of the meteoroid stream. ------------------------------------------ Rainer Arlt & Jurgen Rendtel, 1998 July 7.
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