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Resonant Behaviour of Comet Halley & the Orionid Stream. Aswin Sekhar & David Asher Armagh Observatory United Kingdom. EPSC 2012, Madrid. Brief Background to the History of Comet 1P/Halley. * Observational records date back to 240 B. C. (Yeomans & Kiang 1981).
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Resonant Behaviour of Comet Halley & the Orionid Stream Aswin Sekhar & David Asher Armagh Observatory United Kingdom EPSC 2012, Madrid
Brief Background to the History of Comet 1P/Halley * Observational records date back to 240 B. C. (Yeomans & Kiang 1981) • Accurate orbital elements from 1404 B. C. (Yeomans & Kiang 1981) • Physical life-time assumed to be about 200 revolutions (Whipple 1951) * Dynamical life time of the order of 100,000 years (Hughes 1985, Hadjuk 1986, Steel 1987, Bailey & Emel’yanenko 1996) (Credit: W. Liller, International Halley Watch, 8 March 1986) (Credit: MPS Germany/H. U. Keller)
Brief Introduction to the Interesting Observations of Orionids • Orionids outbursts in 1993 and 2006 were unexpected * Previous works explained the outburst in 2006 using 1:6 mean motion resonance with Jupiter (Rendtel 2007, Sato & Watanabe 2007) (Credit: S. Quirk)
Our Present Work • Halley itself was 1:6 resonant from about 1404 B.C. to 690 B.C. Starting epoch here is 1404 B.C.
* Halley itself was 2:13 resonant from about 240 B.C. to 1700 A.D. Starting epoch here is 240 B.C. 5
Our present calculations show enhanced activity in 1916,1993 & 2070 due to 2:13 resonance mechanism and outbursts in 1436-1440, 1933-1938 & 2006-2010 from 1:6 resonance mechanism • The simulations match the observational records for 1993 (Rendtel & Betlem 1993), 1916 (Olivier 1921), 2006-2010 (Rendtel 2008, IMO records), 1933-1938 (Lovell 1954) & 1436-1440 (Imoto & Hasegawa 1958) very well. 6
History of Comet’s Orbit • Halley’s orbit was substantially different about 12,000 years back Starting epoch here is 240 B.C.
* This sudden change in orbit was due to close encounters with Jupiter Starting epoch is 240 B.C. 10
Intended Future Work • To develop an ejection model to populate meteoroids from 12,000 years in the past • To constrain the orbit of the comet using the ancient & present day meteor records • Meteor showers can be an interesting source to tell us the positions of the comet beyond its recorded observations • Look for diminished meteor rates in some years and treat them with same priority * Negative observations could prove as valuable as enhanced meteor activity possibly Enough of interesting open problems to keep anyone occupied till 2061 (next apparition of Halley)