5011 Ptah

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5011 Ptah
Discovery [1]
Discovered by C. van Houten
I. van Houten
T. Gehrels
Discovery site Palomar Obs.
Discovery date 24 September 1960
MPC designation 5011 Ptah
Named after
Ptah (Egyptian mythology)[2]
6743 P-L · 1983 TF2
Apollo · NEO · PHA
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 55.78 yr (20,373 days)
Aphelion 2.4533 AU
Perihelion 0.8180 AU
1.6357 AU
Eccentricity 0.4999
2.09 yr (764 days)
0° 28m 16.32s / day
Inclination 7.4076°
Earth MOID 0.0247 AU
Physical characteristics
Dimensions 1.56 km (calculated)[3]
0.20 (assumed)[3]

5011 Ptah, provisional designation 6743 P-L, is an eccentric, rare-type asteroid, classified as near-Earth asteroid and potentially hazardous object. It belongs to the group of Apollo asteroids and measures approximately 1.6 kilometers in diameter. It was discovered on 24 September 1960, by Dutch astronomers Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the U.S Palomar Observatory in California.[5] On the same night, the trio of astronomers also discovered the minor planets 1912 Anubis, 1923 Osiris and 1924 Horus, which were also named after Ancient Egyptian deities.

The rare Q-type asteroid orbits the Sun at a distance of 0.8–2.5 AU once every 2 years and 1 month (764 days). Its orbit has a high eccentricity of 0.50 and an inclination of 7° with respect to the ecliptic.[1] As no precoveries were taken, the asteroid's observation arc begins with its discovery observation in 1960.[5]

The potentially hazardous asteroid has a minimum orbit intersection distance with Earth of 0.0247 AU (3,700,000 km) or 9.6 lunar distances. It passes within that distance of Earth 15 times between 1900 and 2100, most recently on 21 January 2007, at 29.6 Gm. The next time will be in 2027 at 28.6 Gm.[1] In addition it is also a Mars-crosser.

The Collaborative Asteroid Lightcurve Link assumes an standard albedo for stony asteroids of 0.20, and calculates a mean diameter of 1.6 kilometers, based on an absolute magnitude of 16.4. No rotational light-curves have been obtained for this asteroid, and its period remains unknown.[3]

The survey designation "P-L" stands for Palomar–Leiden, named after Palomar Observatory and Leiden Observatory, which collaborated on the fruitful Palomar–Leiden survey in the 1960s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of 4,620 minor planets.[6]

The minor planet was named for the creator deity Ptah. In Egyptian mythology, he is the creator of the universe and god of craftsmen and architects. The deity was generally represented in a human form with a sceptre and an ankh.[2] Naming citation was published on 16 May 1992 (M.P.C. 20163).[7]


  1. ^ a b c d e "JPL Small-Body Database Browser: 5011 Ptah (6743 P-L)" (2016-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 11 August 2016. 
  2. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (5011) Ptah. Springer Berlin Heidelberg. p. 431. ISBN 978-3-540-00238-3. Retrieved 11 August 2016. 
  3. ^ a b c d e "LCDB Data for (5011) Ptah". Asteroid Lightcurve Database (LCDB). Retrieved 11 August 2016. 
  4. ^ Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbó, Marco; Hora, Joseph L.; Mueller, Michael (January 2014). "Physical characterization of Warm Spitzer-observed near-Earth objects". Icarus. 228: 217–246. arXiv:1310.2000free to read. Bibcode:2014Icar..228..217T. doi:10.1016/j.icarus.2013.10.004. Retrieved 11 August 2016. 
  5. ^ a b "5011 Ptah (6743 P-L)". Minor Planet Center. Retrieved 11 August 2016. 
  6. ^ "Minor Planet Discoverers". Minor Planet Center. 20 June 2016. Retrieved 10 August 2016. 
  7. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 11 August 2016. 

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