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RE: (meteorobs) WM1 shower?
Also with this comet (Iras-Aracki-Alcock) there is no possibility of an
encounter with the one revolution trail (untill maybe aroud the next
return). Even though the rD of the trail varies by about 0.01 au, the trail
doesn't cross the Earth orbit. So no outburst is expected. However the
orbital period of about one thousand years allows a weak yearly shower. I
recall that there does exist some observations on this. I think that someone
else knows more about this.
Esko
>>>
Kiko Soares wrote:
> I've been thinking about other close aproaches of comets in recent
> times. I know that Iras-Aracki-Alcock has made an aproximation of 4,5
> million km in 1983. Does someone know how it was? Where can I get its
> orbital elements?
Huan Meng wrote:
"
The program by Neslusan et al, which was also mentioned by Hartwig, is
really a useful tool, I think. So I'd like to strongly recommend it to
you. It is below the result calculated for Comet/Iras-Aracki-Alcock with
this tool by the orbital elements that provided by Larry.
>>> EQUINOX: 2000.0; DATA FOR YEAR: 2001
--------------------------------------------------------------------
METH. ALPHA DELTA VG VH L DATE-MAX. D-DISC.
-Q 288.4 44.0 43.77 41.81 49.1 MAY 9.7 .006
-B 288.4 44.0 43.77 41.82 49.1 MAY 9.7 .006
-W 287.0 43.3 43.80 41.81 49.1 MAY 9.7 .046
-A * THIS METHOD IS NOT APPLICABLE IN THAT CASE *
-H 286.6 43.2 43.80 41.82 48.4 MAY 8.9 .043
-P 288.4 44.0 43.77 41.81 49.1 MAY 9.7 .006
Q+ 187.1 -10.3 46.05 35.83 229.1 NOV. 11.5 .974
B+ 135.7 -28.0 32.38 23.17 229.1 NOV. 11.5 .813
W+ * THIS METHOD IS NOT APPLICABLE IN THAT CASE *
A+ * THIS METHOD IS NOT APPLICABLE IN THAT CASE *
H+ 311.1 53.9 42.59 41.77 58.3 MAY 19.2 .479
P+ * THIS METHOD IS NOT APPLICABLE IN THAT CASE *
--------------------------------------------------------------------
FIRST/SECOND (-/+) SET OF DATA CONCERNS THE PRE-/POST-PERIHELION ARC
THE BEST METHOD - PRE-PERIHELION ARC: P (D = .006)
- POST-PERIHELION ARC: H (D = .479) <<<
You see, the minimun value of D-Disc is ONLY 0.006. Such a small value is
sometimes enough to make a meteor shower. But I don't know how about this
one.
=====
> There is a daylight shower coming
> from the general direction of the hyphotetical WM1 radiant. The Omicron
> Cetids have a broad maximum extending from 14/May to 25/May:
http://comets.amsmeteors.org/meteors/showers/omicron_cetids.html
I've got through this web page. The radiant was given as RA=28 deg,
DECL=-3 deg on that page. The result calculated of WM1 is (the orbital
elements used was from http://neo.jpl.nasadot gov/cgi-bin/db?name=2000+WM1)
>>> EQUINOX: 2000.0; DATA FOR YEAR: 2001
--------------------------------------------------------------------
METH. ALPHA DELTA VG VH L DATE-MAX. D-DISC.
-Q 94.1 58.6 46.62 42.38 237.9 NOV. 20.2 .120
-B 95.6 59.2 45.94 41.63 237.9 NOV. 20.2 .115
-W 98.0 64.6 45.94 42.38 237.9 NOV. 20.2 .242
-A 162.4 52.7 46.38 42.48 283.3 JAN. 3.7 .738
-H 104.8 64.3 45.81 42.40 242.2 NOV. 24.4 .232
-P 96.6 61.9 45.41 42.39 240.1 NOV. 22.3 .143
Q+ 36.6 -29.7 45.26 41.88 57.9 MAY 18.8 .010
B+ 36.6 -29.6 45.30 41.92 57.9 MAY 18.8 .010
W+ 36.5 -29.1 45.31 41.88 57.9 MAY 18.8 .020
A+ 39.9 -27.8 45.17 41.87 61.9 MAY 23.0 .067
H+ 36.8 -29.0 45.31 41.88 58.3 MAY 19.2 .020
P+ 36.6 -29.4 45.33 41.88 58.1 MAY 19.0 .011
--------------------------------------------------------------------
FIRST/SECOND (-/+) SET OF DATA CONCERNS THE PRE-/POST-PERIHELION ARC
THE BEST METHOD - PRE-PERIHELION ARC: B (D = .115)
- POST-PERIHELION ARC: B (D = .010) <<<
RA=28 deg, DECL=-3 deg (on that page) is a little bit far away from these
results. So I don't think the omicron-Cetids is a good candidate for WM1
shower.
=========
On another hand, If I remembered correctly, April Lyrids' orbital
elements suggest that the dust trails (meteoroids of the shower) are
short periodic, and the parent comet has had a lot of revolutions so far,
though the comet is long periodic. Are these the reasons why we can see
the Lyrids annually?
PS: Er... I had lots of words on this subject to say just now, but
unfortunately I forgot them now. I'd like to write them next time I'm
free and have enough time to write them down.
All best wishes and Clear skies!
Huan Meng <meteorobs_menhu@hotmail.com>
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If you are interested in complete links on the 2001 LEONIDS, see:
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