(meteorobs) Re: Delta Cancrids
Robert and All,
I believe that the Delta Cancrids are just another slight enhancement of
the continuous antihelion radiant. They DCA's are no different than the
Virginids, Sagittarids, Piscids, or Chi Orionids. These radiants
represent enhancements occurring at other times of the year. The parent
body of the Delta Cancrids and the other showers mentioned are unknown
but are most likely made up not by a single object, but rather a group
or class of asteroids that happen to approach the earth's orbit at
particular times of the year. Since it is not a single source, this may
be the reason the radiant is a wide area rather than a sharp point in
As we progress throughout the year you will find the antihelion position
will overlap the radiants mentioned above during their activity period.
These radiants all have similar characteristics as they all have an
entry velocity near 30 km/sec, producing medium-slow meteors. They all
also possess a population index of 3.0 and ZHR's between 3-5. They also
all lie on the ecliptic near the opposition point so they are best seen
near midnight when they lie highest in the sky.
I hear some of you asking about the Taurids of November? Well they are a
special case as we are looking at a combination of normal antihelion
debris combined with material from Comet Encke. The velocity for the
Taurids is similar to the other antihelion radiants but the comet's
contribution brightens the population index to 2.3 plus increases the
ZHR to 5-10 (combining both Taurid radiants).
Whether you call them Delta Cancrids or antihelion meteors is a personal
matter. They are the same source of meteors and trying to separate them
is unnecessary and a waste of effort.
Robert Gardner wrote:
> I notice that the delta Cancrids' radiant is at RA 8h 40m dec 20o
> The antihelion radiant on January 17 is at RA 8h 42m dec 18.6o
> This is very close for these broad radiants. Will this present any data
> collecting problems.
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