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Re: (meteorobs) Does this shower exist?



In a message dated 10/11/99 9:44:08 AM Eastern Daylight Time, 
rmn@aaocbn.aaodot gov.au writes:

<< Last Friday, I found a new comet (as yet unannounced) that seems to be
 about 13 months from perihelion.  Currently around the distance of
 Jupiter, the comet will have perihelion close to the Earth's orbit.  Sadly
 it will be on the far side of the Sun!  The orbit is still very uncertain,
 but from the short arc, it appears to be best fitted by a parabola.
 However, this doesn't discount the possibility of meteors, and I wondered
 if there was any evidence of meteors having been seen roughly around March
 19 from a radiant at roughly RA 60 deg Dec -25 deg.  Despite the low
 evening elongation, these meteors would be fast.  This would only really
 be a southern hemisphere shower, and is basically a daytime shower.
 
 It won't surprise me that the extended orbital arc will give the nodal
 distance too far from the Earth's orbit for any meteors, but when the
 orbit is published today (?) by the Central Bureau, inevitably someone
 will pick up the possibility of meteors.
 
 Cheers, Rob
 PS As I'm very tired, I wouldn't trust any details I give here (standard
 disclaimer)!
 
 Robert H. McNaught
 rmn@aaocbn.aaodot gov.au >>


First -- congratulations to Rob for being the co-discoverer of this new comet 
(McNaught-Hartley  C/1999 T1).  After getting the latest orbital elements off 
of MPEC 1999-T42, I attempted to answer Rob's question concerning possible 
meteor activity associated with this comet.  

From what I was able to determine, the comet will reach the ascending node of 
its orbit on 2000 December 22.9 (UT) at a distance of 1.173 a.u. from the 
Sun.  The Earth will pass to within 0.176 a.u. of this point roughly 89.4 
days later (2001 March 22.3 UT); Earth being inside the comet orbit.  As for 
the radiant for any possible meteors, I myself found it to be far to the 
south -- perhaps somewhere down in the region around the constellations 
Octans or Apus.  Definetely far out of the reach for us northerners!  

On another note -- although this comet will remain well to the south prior to 
perihelion, it will move rapidly north and east toward the end of 2000 and 
into early 2001 and will arrive at perigee (closest to Earth) around 2001 
January 29 in southern Hercules.  It will then be 1.403 a.u. from the Sun and 
1.338 a.u. from Earth.  If it brightens along the lines of the standard (for 
most comets) inverse fourth-power law, we might expect it to be shining 
around magnitude 9.2 around that time.

-- joe rao
  
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