C/1967 Y1 (Ikeya–Seki)

For the 1965 comet of the same name, see Comet Ikeya-Seki.
C/1967 Y1 (Ikeya–Seki)
Discovery[1]
Discovered byKaoru Ikeya
Tsutomu Seki
Discovery siteJapan
Discovery date28 December 1967
Designations
1967n[2]
1968 I
Orbital characteristics[3]
Epoch18 March 1968 (JD 2439933.5)
Observation arc676 days (1.85 years)
Number of
observations		197
Aphelion4,020 AU
Perihelion1.697 AU
Semi-major axis2,011 AU
Eccentricity0.99916
Orbital period90,185 years
Inclination129.315°
255.321°
Argument of
periapsis		70.864°
Last perihelion25 February 1968
TJupiter–1.02
Earth MOID1.0675 AU
Jupiter MOID0.0276 AU
Physical characteristics[4]
Comet total
magnitude (M1)		4.0
6.7
(1968 apparition)

Comet Ikeya-Seki, formally designated as C/1967 Y1, is a retrograde non-periodic comet discovered by Kaoru Ikeya and Tsutomu Seki on 1967. It is the second comet discovered together by the two Japanese astronomers after C/1965 S1.[1]

Discovery and observations

C/1967 Y1 was the 14th comet discovered in 1967 when both Kaoru Ikeya and Tsutomu Seki spotted it as a 9th-magnitude object on the evening of December 28th.[5] The comet's position remained circumpolar throughout its last perihelion, thus giving astronomers a rare opportunity to observe it all night long.[5]

By 25 February 1968, the comet reached an apparent magnitude of 7.1 and developed a very faint tail.[6] Photometric spectroscopy of the comet's tail together with comets C/1968 L1 and C/1968 N1 has shown its forward scattering to be gray in the 3500–6300 Å spectrum, in contrast to the reddening of the dust tail seen in other comets.[7] The comet was last observed from the Kitt Peak Observatory on 4 November 1969.[4]

References

  1. ^ a b B. G. Marsden (2 January 1968). "Comet Ikeya-Seki (1967n)". Central Bureau for Astronomical Telegrams. 2046.
  2. ^ "Comet Names and Designations". International Comet Quarterly. Retrieved 5 December 2024.
  3. ^ "C/1967 Y1 (Ikeya–Seki) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 5 December 2024.
  4. ^ a b G. W. Kronk (1999). Cometography: A Catalog of Comets. Vol. 5: 1960–1982. Cambridge University Press. pp. 200–205. ISBN 978-0-521-87226-3.
  5. ^ a b D. Milon (March 1968). "New Comet Ikeya-Seki 1967n". Strolling Astronomer. Association of Lunar and Planetary Observers: 209–211. Bibcode:1968StAst..20..209M.
  6. ^ M. J. Gainsford; D. A. Allen; G. S. Pearce (March 1968). "Observations of Comet Ikeya-Seki 1967n". The Astronomer. 4: 218–219. Bibcode:1968StAst..20..209M.
  7. ^ W. L. Gebel (August 1970). "Spectrophotometry of Comets 1967n, 1968b, and 1968c". The Astrophysical Journal. 161: 765–778. Bibcode:1970ApJ...161..765G. doi:10.1086/150577.
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