2008 09 09 The SPE Outbreak

Composite of SPE as seen at YLW


We had to research questions, does the radiant of the outbreak members coincide with the September Perseid Shower’s radiant and is the orbit that of a long period comet or is it a short period comet.

Here is a comparison between the data from the IMO shower list, Molau’s Shower 68 and those derived form the BC videos.

IMO                 BC                  Shower 68

λsol    166°7            166.9089           n/a

α         60°                47.7°              48.0°

δ         47°              +39.5°             39.5°

Vinf 64 km/s          65.47 km/s     65 km/s

ZHR      5                  ˜25                  n/a

The best fit is with Sirko Molau’s (Molau 2008) Shower 68 and not the SPE.  Much more research is needed before we can declare this is true or just a coincidence. This should be an open question.

As Esko calculations show the source for this outbreak is in a Jupiter crossing orbit with a mean period of 78.54 years. This puts it into a Halley type orbit (short period).

More to come…

Orbital parameters (equinox J2000)
year: 2008
month: 9
day: 9.347222
q(AU): 0.719
a (AU): 18.34
e: 0.961
i (deg): 139.08
omega: 245.36
node: 166.909
pi: 52.27
Vinf: 65.47 km/s
Vgeo: 64.32 km/s
Vh: 41.39 km/s

Period: 78.54 years
Q (AU): 35.96
1/a: 0.055
Solar Long: 166.9089

Heliocentric Radiant
ß   33.77
λ   37.38
Vh 41.39 km/s

α Geo 47.40
δ Geo +39.50
Days to perihelion: 36.7
Orbit: ecliptic retrograde
Meets in: descending node
Ratio of revolution to Jupiter: 0.15:1
Jupiter crossing: Yes

Observed Radiant Position

Local sidereal time -6.245 deg or an hour angle of 306.49
Data for equinox date: Ra: 42.27 Dec: +39.57
Data equinox J2000: RA 47.28 Dec: +39.53
Vinf: 65.47 km/s

Geocentric Radiant Position
Local sidereal time: -6.245 deg or an hour angle of 306.37
Data for equinox date: Ra: 47.38 Dec: +39.53
Data equinox J2000: RA: 47.40 Dec: +39.50
Vgeo:  64.32 km/s

Refs cited and develop Shower 68 discussion edited: 2010-09-24 by jlb

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