Comet 50P on 4 November 1951
Discovered bySylvian Arend
Discovery dateOctober 4, 1951[1]
1951 Q4, 1959 O4
Orbital characteristics
Aphelion6.2531 AU
Perihelion1.9237 AU[2]
Semi-major axis4.0884 AU
Orbital period8.27 a
Last perihelion2016-Feb-08[3]
November 1, 2007[3]
Next perihelion2024-May-12[4]

Comet Arend or 50P/Arend is a periodic comet in the Solar System which was discovered on October 4, 1951.[1] It was discovered by astronomer Sylvain Julien Victor Arend[1] at the Royal Observatory of Belgium located in the municipality of Uccle. The comet was illustrated at approximately a magnitude of 14 and also exhibited a nucleus within a coma 14 arc seconds across. From its discovery, the comet has had 7 perihelions with its last return of Earth recorded on November 1, 2007.[3][5][6][7][8] The comet's next perihelion will be in the year 2024.[9][10]


50P/Arend was observed at its brightest at a maximum magnitude of 14 when it was discovered in 1951. At the comet's next apparition on September 1, 1959, did not exceed 17 if it had not been for an outburst in November which affected its brightness to magnitude 15.5. The observed orbital period was 7.8 years at the time of its discovery however at each succeeding perihelion has led to less favorable observations due to its 0.64 astronomical units (AU) as it approached Jupiter in 1969, even if its maximum magnitude was 15. This approach also led to the comet's orbital period to increase to 8.0 years.[1]

Long-term motion studies conducted by Brian G. Marsden on the comet 50P/Arend renders the comet's orbital eccentricity at 0.5 which makes it relatively undisturbed by Jupiter over the last 200-year cycles despite as passage of only 0.49 AU.[1][11][12][13] The study was conducted inside the interval where libration happens. Several comets, namely 50P/Arend, 4P/Faye, 6P/d'Arrest, 22P/Kopff, 36P/Whipple, 78P/Gehrels, 92P/Sanguin, 4015 Wilson-Harrington, and 128P/Shoemaker-Holt, were observed at the Palomar Observatory. Visible coma activity was only observed from 4P/Faye and 50P/Arend out of the 9 other comets from data obtained in May 2000 and March 2001.[14] There have been 1069 observations from October 8, 1951, to February 19, 2008, also where its mean residual is at 0".60.[15]

The nucleus of the comet has a radius of 0.95 ± 0.03 kilometers, assuming a geometric albedo of 0.04.[16]


  1. ^ a b c d e "50P/Arend". Gary W. Kronk's Cometography. Retrieved 2010-03-02.
  2. ^ "JPL Small-Body Database Browser: 50P/Arend" (2009-03-19 last obs). Jet Propulsion Laboratory. Retrieved 2012-02-18.
  3. ^ a b c "50P/Arend". Aerith. Retrieved 2010-03-02.
  4. ^ MPC
  5. ^ "50P/Arend (2007)". Aerith. Retrieved 2010-03-02.
  6. ^ "Periodic Comet 50P/Arend". H. Mikuz, Crni Vrh Observatory, Slovenia. Retrieved 2010-03-02.
  7. ^ "Catalog of Hubble Space Telescope Comet Observations". The Planetary Data System (PDS) Small Bodies Node (SBN). Archived from the original on 2010-06-01. Retrieved 2010-03-02.
  8. ^ "COMETA 50P (Arend)". U.A.I. SEZIONE COMETE. Archived from the original on 2011-07-22. Retrieved 2010-03-02.
  9. ^ "Numbered periodic comets index in perihelion year". JComet Observations. Retrieved 2010-03-08.
  10. ^ "Cometas Periódicos (Periodic Comets)". Cometografia. Retrieved 2010-03-08.
  11. ^ Belbruno, E. & Marsden, B. G. (1997). "Resonance Hopping in Comets". Astronomical Journal. 113: 1433. Bibcode:1997AJ....113.1433B. doi:10.1086/118359.
  12. ^ "The Minor Planet Electronic Circulars contain information on unusual minor planets and routine data on comets". Brian G. Marsden MPC. Archived from the original on 11 April 2010. Retrieved 2010-03-02.
  13. ^ Lowry, S; Weissman, Paul R (2003). "The colors of cometary nuclei—Comparison with other primitive bodies of the Solar System and implications for their origin". Icarus. 164 (2): 492. Bibcode:2003Icar..164..492L. doi:10.1016/S0019-1035(03)00129-5.
  14. ^ Lowry, Stephen C.; Weissman, Paul R. (2003). "CCD observations of distant comets from Palomar and Steward Observatories". Icarus. 164 (2): 492–503. Bibcode:2003Icar..164..492L. doi:10.1016/S0019-1035(03)00129-5.
  15. ^ "50P/Arend". Comet Orbit. Retrieved 2010-03-02.
  16. ^ Lamy, P. L.; Toth, I.; Weaver, H. A.; A'Hearn, M. F.; Jorda, L. (December 2009). "Properties of the nuclei and comae of 13 ecliptic comets from Hubble Space Telescope snapshot observations". Astronomy & Astrophysics. 508 (2): 1045–1056. doi:10.1051/0004-6361/200811462. S2CID 125249770.