55P/Tempel–Tuttle (commonly known as Comet Tempel–Tuttle) is a retrograde periodic comet with an orbital period of 33 years. It fits the classical definition of a Halley-type comet with a period of between 20 and 200 years. It was independently discovered by Wilhelm Tempel on 19 December 1865, and by Horace Parnell Tuttle on 6 January 1866. It is the parent body of the Leonid meteor shower.

Observational history

left|thumb|Sketch of the comet as it was discovered by [[Wilhelm Tempel on 19 December 1865.]]

In 1699, it was observed by Gottfried Kirch, however it was not recognized as a periodic comet until the discoveries by Tempel and Tuttle during the 1866 perihelion. In 1933, S. Kanda deduced that the comet of 1366 was Tempel–Tuttle, which was confirmed by Joachim Schubart in 1965. On 26 October 1366, the comet passed from Earth. During the 1998 apparition the comet brightened more than predicted and reached an apparent magnitude of 7.4–7.8 in late February and could be observed with binoculars. It was last observed on 5 July 1998.

Physical characteristics

The nucleus of the comet was observed by Hubble Space Telescope during the 1998 apparition, and assuming an albedo of 0.04, its nucleus was estimated to have a mean radius of 1.8 km. Spectrometric observations of its nucleus reveal that it has a reddish color, with a B−V of and V−R of . A jet was observed emanating from the nucleus and based on its movement the rotation period was calculated to be between and hours.

The spectrum of the comet revealed the presence of diatomic carbon, NH2 and [Oi]. The relative production rates indicate that the comet is depleted in diatomic carbon, with the gas-to-dust ratio also indicated it was gas rich compared with Halley's Comet. The infrared spectrum of the comet closely resembled that of a black body with a temperature of 330 K and lacked silicate emission that has been detected in other comets.

William Huggins observed the spectrum of the comet in January 1866, making it the second time spectrographic observations of a comet were obtained.

55P/Tempel–Tuttle is estimated to have a total nuclear mass of 1.2 kg, with its meteoroid stream is estimated to have a mass of 5 kg in total.

Orbit

{| class="wikitable sortable" style="font-size: 0.9em;"

|+55P/Tempel–Tuttle Earth approaches

! Year

! Nominal geocentric<br />distance (AU)

|-

|1366 || Between 2021–2030, Earth will often pass through the meteoroid stream left behind from the 1733 orbit.

See also

  • Cometary close approaches to Earth
  • D/1770 L1 (Lexell)
  • C/1983 H1 (IRAS–Araki–Alcock)
  • 252P/LINEAR
  • 460P/PanSTARRS

References

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Bibliography

  • 55P/Tempel–Tuttle at Gary W. Kronk's Cometography
  • 55P/Tempel–Tuttle at Seiichi Yoshida's website