4450 Pan

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For the moon of Saturn, see Pan (moon). For other uses, see Pan (disambiguation).
4450 Pan
Discovery [1]
Discovered by C. Shoemaker
E. Shoemaker
Discovery site Palomar Obs.
Discovery date 25 September 1987
MPC designation (4450) Pan
Named after
Pan (Greek deity)[2]
1987 SY · 1937 CA
Apollo · NEO · PHA
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 28.22 yr (10,306 days)
Aphelion 2.2883 AU
Perihelion 0.5962 AU
1.4423 AU
Eccentricity 0.5866
1.73 yr (633 days)
0° 34m 8.4s / day
Inclination 5.5198°
Earth MOID 0.0285 AU
Physical characteristics
Dimensions 1.0±0.2 km[3]
1.13 km (calculated)[4]
3.51±0.02 h[5]
56.48±0.02 h[6]
60±12 h[a]
0.20 (assumed)[4]
17.1[1][4] · 17.43±0.07[3]

4450 Pan, provisional designation 1987 SY, is a highly eccentric, contact-binary[7] asteroid, classified as a near-Earth asteroid and potentially hazardous object. It belongs to the group of Apollo asteroids and measures approximately 1.1 kilometers in diameter. It was discovered on 25 September 1987, by American astronomers Eugene and Carolyn Shoemaker at the U.S Palomar Observatory in California.[8]

The stony S-type asteroid orbits the Sun at a distance of 0.6–2.3 AU once every 633 days (1 year and 9 months). Its orbit has an eccentricity of 0.59 and an inclination of 6° with respect to the ecliptic.[1] As an Apollo asteroid, it is an Earth-crosser and has a minimum orbit intersection distance with Earth of 0.0283 AU (4,230,000 km) or 11.0 lunar distances. In addition, due to its extremely eccentric orbit, it is also a Venus- and Mars-crosser and approaches Mercury within 20 Gm. Its first observation was made at Heidelberg Observatory in 1937, yet it remained unused and the asteroid's observation arc begins with its discovery observation in 1987.[8]

The asteroid is a contact binary, composed of two lobes in mutual contact, held together only by their weak gravitational attraction, and typically show a dumbbell-like shape (also see 4769 Castalia).[7] A large number of near-Earth objects are thought to be contact binaries.[9] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.1 kilometers,[4] while photometric observations by Italian Albino Carbognani at Saint-Barthelemy Observatory (B04) gave a diameter of 1.0±0.2 kilometers.[3]

In September 2013, a rotational light-curve of this asteroid was obtained from photometric observations by U.S. astronomer Brian D. Warner at his Palmer Divide Station in Colorado. It gave a long rotation period of 56.48±0.02 hours with a brightness variation of 0.64 in magnitude (U=3).[6] The well-defined period superseds two previous observations by Petr Pravec at Silvano Casulli that gave a period of 60±12 and 3.51±0.02 hours, respectively.(U=2/1).[a][5]

The minor planet was named after Pan, the Greek god of nature, shepherds of flocks and wild animals. In art, he was represented as a horned half-man, half goat. Pan was worshiped by the citizens of Athens, after he had inspired panic in the hearts of their Persians enemies in the Battle of Marathon (also see 4356 Marathon). The modern word "panic" origins from this myth. The name Pan has also been given to Saturn XVIII, one of the moons of Saturn.[2] Naming citation was published on 30 January 1991 (M.P.C. 17657).[10]


  1. ^ a b Pravec (2008) web: rotation period 60±12 hours with a brightness amplitude of 0.6 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (4450) Pan
  1. ^ a b c d "JPL Small-Body Database Browser: 4450 Pan (1987 SY)" (2015-12-13 last obs.). Jet Propulsion Laboratory. Retrieved 5 December 2016. 
  2. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (4450) Pan. Springer Berlin Heidelberg. p. 382. ISBN 978-3-540-00238-3. Retrieved 11 August 2016. 
  3. ^ a b c Carbognani, Alberto (September 2008). "Lightcurve Photometry of NEAs 4450 Pan, (170891) 2004 TY16 2002 RC118, and 2007 VD12". The Minor Planet Bulletin. 35 (3): 109–110. Bibcode:2008MPBu...35..109C. ISSN 1052-8091. Retrieved 11 August 2016. 
  4. ^ a b c d e "LCDB Data for (4450) Pan". Asteroid Lightcurve Database (LCDB). Retrieved 11 August 2016. 
  5. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (4450) Pan". Geneva Observatory. Retrieved 11 August 2016. 
  6. ^ a b Warner, Brian D. (April 2014). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2013 September-December". The Minor Planet Bulletin. 41 (2): 113–124. Bibcode:2014MPBu...41..113W. ISSN 1052-8091. Retrieved 11 August 2016. 
  7. ^ a b Lance A. M. Benner (2013-11-18). "Binary and Ternary near-Earth Asteroids detected by radar". NASA/JPL Asteroid Radar Research. Retrieved 2014-03-01. 
  8. ^ a b "4450 Pan (1987 SY)". Minor Planet Center. Retrieved 11 August 2016. 
  9. ^ Michael Busch (2012-03-12). "Near-Earth Asteroids and Radar Speckle Tracking" (PDF). Retrieved 11 August 2016. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 11 August 2016. 

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