6344 P-L

From Wikipedia, the free encyclopedia
  (Redirected from 2007 RR9)
Jump to: navigation, search
6344 P-L
Discovery [1][2]
Discovered by PLS (uncredited)
Discovery site Palomar Obs.
Discovery date 1960
MPC designation 6344 P-L
2007 RR9
Apollo · NEO · PHA[1][2]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 47.36 yr (17,298 days)     
Aphelion 4.6744 AU
Perihelion 0.9327 AU
2.8036 AU
Eccentricity 0.6673
4.69 yr (1,715 days)
Inclination 4.7248°
Earth MOID 0.02823 AU
Physical characteristics
Dimensions 200–500 m (calculated)[3]

6344 P-L is an Apollo, near-Earth, potentially hazardous asteroid that was discovered in the year 1960 by astronomers and asteroid searchers Tom Gehrels, Ingrid van Houten-Groeneveld, and Cornelis Johannes van Houten during the Palomar–Leiden survey. However, since the body is still unnumbered, the discoverers have not yet been officially determined. Last seen in 1960, it was lost, but rediscovered in 2007 as 2007 RR9.[4] In other words, it was a lost asteroid from 1960 until it was recovered and recognized as the same object by Peter Jenniskens in 2007.[5]

It is either an asteroid or dormant comet nucleus, and it has a 4.7-year orbit around the Sun.[5] The orbit goes out as far as Jupiter's but then back in, passing as close as 0.07 AU to the Earth, making it a collision risk.[5]

The minor planet classifies as a potentially hazardous object with an Earth minimum orbit intersection distance of 0.02823 AU (4,220,000 km), equivalent to 11 lunar distances.[1] It has an estimated diameter of approximately 200–500 meters, based on an absolute magnitude of 20.4.[3] Although it was not outgassing at the time of its recovery, it is probably a dormant comet.[5]

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. Tom Gehrels used Palomar's 48-inch Samuel Oschin telescope and shipped the photographic plates to the van Houten's at Leiden Observatory, where astrometry was carried out. The trio are credited with more than 4600 minor planet discoveries.[6]


  1. ^ a b c d e "JPL Small-Body Database Browser: (6344 P-L)" (2008-02-03 last obs.). Jet Propulsion Laboratory. Retrieved 1 June 2016. 
  2. ^ a b "6344 P-L". Minor Planet Center. Retrieved 1 June 2016. 
  3. ^ a b "Absolute Magnitude (H)". NASA/JPL. Retrieved 1 June 2016. 
  4. ^ Mohit Joshi (10 May 2007). "Long-lost 'Potentially Hazardous Asteroid' re-located". TopNews. Retrieved 20 August 2016. 
  5. ^ a b c d "Long-Lost, Dangerous Asteroid Is Found Again". ScienceDaily. 15 October 2007. Retrieved 1 June 2016. 
  6. ^ "Minor Planet Discoverers". Minor Planet Center. 20 August 2016. Retrieved 20 August 2016. 

External links[edit]