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 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 53.94 yr (19,701 days)    
Aphelion 2.4533 AU
Perihelion 0.8177 AU
1.6355 AU
Eccentricity 0.5000
2.09 yr (764 days)
Inclination 7.4075°
Earth MOID 0.0248 AU
Physical characteristics
Dimensions 1.56 km (calculated)[3]
0.20 (assumed)[3]

5011 Ptah, provisional designation 6743 P-L, is a rare-type, highly eccentric asteroid, classified as potentially hazardous object and Apollo asteroid, about 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.[4]

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 is tilted by 7 degrees to the plane of the ecliptic and shows an exceptionally high eccentricity of 0.50. The Collaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.20.[3] As a potentially hazardous asteroid, it has a short Earth minimum orbit intersection distance (MOID) of 0.025 AU. 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, the asteroid crosses the orbit of Mars and classifies as a Mars-crosser. As of 2016, the asteroid's rotation period remains unknown.[3]

The 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 Cornelis and Ingrid van Houten at Leiden Observatory, where astrometry was carried out. The trio are credited with several thousand asteroid discoveries.[5]

The minor planet was named for Ptah, the creator of the universe and a patron of craftsmen, especially sculptors, in Egyptian mythology. Ptah was originally the local deity of Memphis, capital of Egypt from the 1st dynasty; the political importance of Memphis led to the expansion of Ptah's cult throughout Egypt. The deity was always represented in purely human form, often swathed in a winding sheet.[2] On the same night Ptah was discovered, the trio of astronomers also discovered the minor planets 1912 Anubis, 1923 Osiris and 1924 Horus, which are also named after Ancient Egyptian deities.


  1. ^ a b c d "JPL Small-Body Database Browser: 5011 Ptah (6743 P-L)" (2014-09-02 last obs.). Jet Propulsion Laboratory. Retrieved March 2016.  Check date values in: |access-date= (help)
  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 March 2016.  Check date values in: |access-date= (help)
  3. ^ a b c d e "LCDB Data for (5011) Ptah". Asteroid Lightcurve Database (LCDB). Retrieved March 2016.  Check date values in: |access-date= (help)
  4. ^ "5011 Ptah (6743 P-L)". Minor Planet Center. Retrieved March 2016.  Check date values in: |access-date= (help)
  5. ^ "Minor Planet Discoverers". Minor Planet Center. 23 March 2016. Retrieved March 2016.  Check date values in: |access-date= (help)

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