46P / Wirtanen

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46P / Wirtanen [i]
Comet 46P Wirtanen STSCI-H-p1863.png
Image taken by the Hubble Space Telescope on December 20, 2018
Properties of the orbit ( animation )
Orbit type short-term
Numerical eccentricity 0.659
Perihelion 1.055 AU
Aphelion 5.126 AU
Major semi-axis 3,095 AU
Sidereal period 5 a 158 d
Inclination of the orbit plane 11.746 °
Perihelion December 12, 2018
history
Explorer CAWirtanen
Date of discovery January 18, 1948
Older name 1961 IV; 1960m;
1967 XIV; 1967k;
1974 XI; 1974i;
1986 VI; 1985q;
1991 XVI; 1991s;
46P / 1948 A1;
1947 XIII; 1948b;
46P / 1954 R2;
1954 XI;
1954j
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

46P / Wirtanen is a short-period comet with an orbital period of 5.4 years around the sun . This makes it one of the ten tail stars with the shortest period.

It belongs to the comets of the Jupiter family , all of which are characterized by an aphelion of 5 to 6 AU . The radius of the comet's nucleus is estimated to be 555 ± 40 m. The rotation period is 6–7.5 hours.

discovery

46P / Wirtanen was discovered in a photograph on January 17, 1948 by the American astronomer CA Wirtanen . The photo plate was taken on January 15th during an inventory of stellar self-motions .

Change of path

Since its discovery in 1948, 46P / Wirtanen has had two close encounters with the planet Jupiter that dramatically affected its orbit around the sun. In 1972 the distance to Jupiter was only 0.28  AU , in 1984 it was 0.46 AU. The perihelion of its orbit around the sun was thereby shortened from 1.63 AU to 1.06 AU and the orbital period accordingly from 6.71 years to 5.46 years.

Target for the Rosetta mission

46P / Wirtanen was the originally planned target spacecraft Rosetta of ESA . The start of the Rosetta mission was originally scheduled for January 12, 2003. After the first launch of an Ariane 5 ECA launcher (Flight 157) failed on December 11, 2002 , the launch of the Rosetta mission had to be postponed. The starting window for 46P / Wirtanen could not be kept and the comet became inaccessible for Rosetta.

Comet 67P / Churyumov-Gerasimenko , also a member of the Jupiter family, was chosen as a replacement target for the Rosetta mission . The launch took place on March 2, 2004 and the mission was largely successful.

Near Earth in December 2018

On December 16, 2018, the comet came particularly close to Earth and flew past Earth in 0.0781 AU (11,680,000 km; ~ 30 times the lunar distance). The brightness reached about magnitude 4.

See also

Web links

Commons : 46P / Wirtanen  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b M. Verdant & GH Schwehm: The International Rosetta Mission. In: ESA Bulletin , No. 93, pp. 39–50, 1998. (digitized version )
  2. ↑ H. Boehnhardt, C. Delahodde, T. Sekiguchi, GP Tozzi, R. Amestica, O. Hainaut, J. Spyromilio, M. Tarenghi, RM West, R. Schulz & G. Schwehm: VLT observations of comet 46P / Wirtanen . In: Astronomy & Astrophysics , Vol. 387, pp. 1107–1113, 2002. (digitized version )
  3. ^ G. Merton: Council Report on Comets in 1948. In: Monthly Notices of the Royal Astronomical Society , Vol. 109, pp. 248-257, 1949. (digitized version )
  4. ↑ a b K.-H. Glassmeier, H. Boehnhardt, D. Koschny, E. Kühr & I. Richter: The Rosetta Mission: Flying towards the Origin of the Solar System. In: Space Science Reviews , Vol. 128, pp. 1–21, 2007. (digitized version)
  5. ^ ESA: Announcement of Rosetta Launch Delay. ESA press release of January 6, 2003 Accessed on August 24, 2018
  6. ^ Arianespace: Arianespace Flight 157: The Inquiry Board Submits its Findings. Arianespace press release January 7, 2003 Accessed August 24, 2018
  7. ↑ a b ESA: Rosetta - A new Target to Solve Planetary Mysteries. ESA press release of January 26, 2004 Accessed on August 24, 2018
  8. ↑ Brightest Comet Of 2018 To Light Up The Sky In December , accessed October 27, 2018