23712 Willpatrick

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
23712 Willpatrick
Discovery [1]
Discovered by W. G. Dillon
E. R. Dillon
Discovery site George Obs. (735)
Discovery date 1 January 1998
MPC designation (23712) Willpatrick
Named after
William Patrick Dillon
(discoverer's son)[2]
1998 AA
main-belt · Phocaea[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 63.21 yr (23,086 days)
Aphelion 2.9614 AU
Perihelion 1.7890 AU
2.3752 AU
Eccentricity 0.2468
3.66 yr (1,337 days)
0° 16m 9.48s / day
Inclination 23.493°
Physical characteristics
Dimensions 3.47±0.45 km[5]
5.28 km (calculated)[3]
7.660±0.187 km[6][7]
3.902±0.005 h[8][a]
0.23 (assumed)[3]
13.6[1][3] · 13.5[6] · 13.85±0.23[9] · 13.97[5]

23712 Willpatrick, provisional designation 1998 AA, is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter.

The asteroid was discovered on 1 January 1998, by American astronomers Elizabeth and William G. Dillon at George Observatory in Needville, Texas, who later named it after their son William Patrick Dillon.[2][10]

Orbit and classification[edit]

Willpatrick is a member of the Phocaea family (701),[4] a group of stony asteroids with similar orbital characteristics.[3] It orbits the Sun in the inner main-belt at a distance of 1.8–3.0 AU once every 3 years and 8 months (1,337 days). Its orbit has an eccentricity of 0.25 and an inclination of 23° with respect to the ecliptic.[1]

The first precovery was taken during the Digitized Sky Survey at Palomar Observatory in January 1954, extending the asteroid's observation arc by 44 years prior to its official discovery observation at Needville.[10]

Physical characteristics[edit]


In September 2004, a rotational lightcurve of Willpatrick was obtained by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado. The photometric observations rendered a well-defined rotation period of 3.902 hours with a brightness variation of 0.40 magnitude (U=3).[8][a]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Willpatrick measures between 3.47 and 7.7 kilometers in diameter and its surface has an albedo between 0.12 and 0.44.[5][6][7]

The Collaborative Asteroid Lightcurve Link assumes a family-specific albedo of 0.23 – derived from 25 Phocaea, the namesake of the Phocaea family – and calculates a diameter of 5.3 kilometers with an absolute magnitude of 13.6.[3]


This minor planet was named after the discoverer's son, William Patrick Dillon (born 1992), who was present on the night this minor planet was discovered. His words "Daddy, I want to go home now. This place is cold and spooky." made it into the naming citation of the Minor Planet Circulars (MPCs).[2] The approved naming citation was published by the Minor Planet Center on 28 September 2004 (M.P.C. 52769).[11]


  1. ^ a b Lightcurve plot of 23712 Willpatrick, Palmer Divide Observatory, B. D. Warner (2004) rotation period of 3.902±0.005 hours with a brightness amplitude of 0.40±0.02 magnitude.


  1. ^ a b c d "JPL Small-Body Database Browser: 23712 Willpatrick (1998 AA)" (2017-03-19 last obs.). Jet Propulsion Laboratory. Retrieved 27 June 2017. 
  2. ^ a b c Schmadel, Lutz D. (2006). Dictionary of Minor Planet Names – (23712) Willpatrick, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 186. ISBN 978-3-540-34360-8. Retrieved 1 January 2016. 
  3. ^ a b c d e f g "LCDB Data for (23712) Willpatrick". Asteroid Lightcurve Database (LCDB). Retrieved 17 May 2016. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 1 November 2017. 
  5. ^ a b c d Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923Freely accessible. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 27 June 2017. 
  6. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 17 May 2016. 
  7. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 3 December 2016. 
  8. ^ a b Warner, Brian D. (June 2005). "Asteroid lightcurve analysis at the Palmer Divide Observatory - fall 2004". The Minor Planet Bulletin. 32 (2): 29–32. Bibcode:2005MPBu...32...29W. ISSN 1052-8091. Retrieved 17 May 2016. 
  9. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 17 May 2016. 
  10. ^ a b "23712 Willpatrick (1998 AA)". Minor Planet Center. Retrieved 1 January 2016. 
  11. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 May 2016. 

External links[edit]