(meteorobs) Early January Meteor Shower?

Roberto Gorelli md6648 at mclink.it
Mon Nov 23 06:07:22 EST 2015


On Sun, 22 Nov 2015 13:51:42 +1100
  David Seargent <seargent at ozemail.com.au> wrote:
> Dear all,
> 
> I hope that someone on this list might be able to shed light on, 
>what is for me, a long standing mystery!
> Once upon a time when I was young (January 1, 1971 actually) I was 
>entertaining a couple of friends by showing them the "usual suspects" 
>through my telescope when our attention was arrested by a beautiful 
>meteor of magnitude -1 or -2 travelling northward almost overhead. No 
>sooner had this faded out than another - this time faint - meteor 
>fell in the south-west having a trajectory roughly perpendicular to 
>the extended path of the first. I remarked that "there must be a 
>meteor shower" in progress and kept looking in the region of sky for 
>a further couple of minutes when another faint meteor, also 
>apparently radiating from the same general area of sky, rewarded our 
>attention. Concluding that a shower of (mainly very faint) meteors 
>must be in progress, but with a list of telescopic objects on the 
>night's menu, we went back to the telescope. Nevertheless, over the 
>next hour or thereabouts, we paused several times to "see if the 
>meteors are still coming" and, each time, needed only to look for two 
>or three minutes before seeing another faint one, all apparently 
>coming from the same source. From the (short) length of time needed 
>to spot one, I assumed that this shower was quite active, with a ZHR 
>of around 20 or so. Altogether, we counted 7 meteors during these 
>rather cursory glances. Assuming that the shower was a known one, I 
>did not try to determine a radiant per se, although noting that the 
>meteors appeared to be issuing from around Hydrus or Toucan or near 
>the boundary of these constellations. All of the meteors, except the 
>first, were small and faint (about mag. 4.5 - 5) and were without 
>trail or spark train. The initial one seemed different and may not 
>have been associated, although its trajectory was broadly similar.
> During the following days I contacted some meteor observers to find 
>out more about the shower, and was surprised to find that no shower 
>from that area at that date was known. I even telephoned the State 
>Observatory in Sydney, but once again nothing was known of a shower. 
>I observed the region on the following night, but saw nothing. The 
>following year, I looked again on the same date, but no meteors. I 
>have looked once or twice over the years but have not noticed any 
>activity from that region. Needless to say, I have searched several 
>apparently comprehensive catalogues of meteor showers, but found 
>nothing listed!
> I have since attempted a *VERY APPROXIMATE* derivation of the 
>radiant and arrived at 
> 
> RA = 20 degrees,  Dec. = -65 degrees 
> 
> Recently, I looked up the list of theoretical radiants for meteors 
>from long-period comets given by J. Drummond (Icarus 1981) and found 
>an entry for C/1920 X1 (Skjellerup) [= 1920 III]  on January 2 at,
> 
> RA = 20 degrees, Dec. = -63 degrees.
> 
> This looks pretty impressive, but Drummond gives the predicted Vg as 
>just 16 kms/sec. As I recall, the faint meteors seemed rather swift, 
>although perhaps their short paths and brief duration has confused my 
>memory into thinking that they were faster than in actual fact. After 
>all, it was a long time ago! (The bright meteor was, however, slow. 
>Ironically, that is the one I have most suspected as being a random 
>sporadic!)
> I am about 70% convinced that the shower was real, although I am 
>less secure about the accuracy of the radiant co-ordinates  and, in 
>any case, suspect that the radiant was likely quite diffuse. It does 
>seem strange that a shower of that strength was not reported, but 
>there are some reasons why it might have been missed. The radiant was 
>very far south, the meteors were faint and the event occurred in the 
>middle of the holiday season - the very next evening following New 
>Year's Eve celebrations! Moreover, the lack of activity on the 
>following night implies short duration. Maybe this was a very brief 
>outburst and I was simply in the right place at the right time.
> Does any member of this list have any information regarding possible 
>activity in that region during late December or early January, or 
>even information about any other theoretical radiants in that part of 
>the sky around that time? Any feedback would be most welcome.
> Clear skies,
> David Seargent

You must remember that, too it is improbable, it's possible that an 
meteor observer can to see in a same night a certain number of meteors 
that apparently come from a same radiant.
Seven meteors in a night are at the border from a low ZHR meteor 
shower and an apparent (no real) meteor shower, in this way it's 
possible too that in a century of observations in all the World 
somebody somewhere can to see until 10-20 sporadic meteors that 
casually appear to come from a same radiant.
You must too remember that the Southern skys are non entire explored 
for meteor showers, as for example the radiant of C/1920 X1 
Skjellerup, that in the past or in the future shall origine certainly 
to a meteor shower.
I think that peoples in Southern emisphere should pay attention at all 
this "little events" for future biggest events.
Two day ago was the 20° anniversary of the 4° rain of November 
Monocerontids (somebody watched for it?), they are a meteor shower 
that occur only during 20-40 minutes each 10 years with 200 and more 
ZHR (and probably not all 10 years), how many similar showers occur in 
Southern sky?
Best greetings.
Roberto Gorelli


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