1625 The NORC

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1625 The NORC
Discovery [1]
Discovered by S. Arend
Discovery site Uccle Obs.
Discovery date 1 September 1953
MPC designation (1625) The NORC
Named after
(Naval Ordnance Research Calculator)[2]
1953 RB · 1929 CA
1935 EN · 1936 QS
1942 RK · 1947 NG
1953 QK · 1954 UL1
A914 SA
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 102.34 yr (37,380 days)
Aphelion 3.9236 AU
Perihelion 2.4606 AU
3.1921 AU
Eccentricity 0.2292
5.70 yr (2,083 days)
0° 10m 22.08s / day
Inclination 15.552°
Physical characteristics
Dimensions 44.66±2.09 km[4]
47.60 km (calculated)[3]
53.317±0.176 km[5]
55.863±1.536 km[6]
61.76±17.49 km[7]
75.11±0.80 km[8]
12.94±0.01 h[9]
13.8113±0.0071 h[10]
13.959±0.004 h[11]
18.820±0.770 h[12]
0.057 (assumed)[3]
Tholen = C[1] · C[3]
B–V = 0.732[1]
U–B = 0.311[1]
10.043±0.001 (R)[10] · 10.070±0.080 (R)[12] · 10.34[1][3][4][6][7][8]

1625 The NORC, provisional designation 1953 RB, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 55 kilometers in diameter. It was discovered on 1 September 1953, by Belgian astronomer Sylvain Arend at the Royal Observatory of Belgium in Uccle, Belgium.[13] It was named after the IBM Naval Ordnance Research Calculator (NORC).[2]

Orbit and classification[edit]

The NORC orbits the Sun in the outer main-belt at a distance of 2.5–3.9 AU once every 5 years and 8 months (2,083 days). Its orbit has an eccentricity of 0.23 and an inclination of 16° with respect to the ecliptic.[1] The asteroid was first identified as A914 SA at Heidelberg Observatory in 1914. Its observation arc begins 24 years prior to its official discovery observation, when it was identified as 1929 CA at Uccle.[13]

Physical characteristics[edit]

In the Tholen classification, The NORC is a common carbonaceous C-type asteroid.[1]


Between 2009 and 2014, five rotational light-curve were obtained of The NORC from photometric observations taken by René Roy, David Higgins and the Palomar Transient Factory. The light-curves gave a rotation period between 12.94 and 18.820 hours with a change in brightness of 0.06 to 0.33 in magnitude (U=+1/2/3-).[9][10][12] The best rated result with a period of 13.959 hours (Δmag 0.16) was obtained by Australian amateur astronomer David Higgins.[11]

Diameter and albedo[edit]

According to the surveys carried out by Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, The NORC measures between 44.66 and 75.11 kilometers in diameter, and its surface has an albedo of 0.023 and 0.065.[4][5][6][7][8] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 47.60 kilometers using an absolute magnitude of 10.34.[3]


This minor planet was named after the IBM Naval Ordnance Research Calculator (NORC), IBM's first-generation vacuum tube computer built in the 1950s (also see List of vacuum tube computers and § External links). NORC was the fastest, most powerful electronic computer of its time. Under the direction of Wallace J. Eckert, after whom the asteroid 1750 Eckert is named, NORC performed a vast amount of orbital calculations for minor planet.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 1591).[14]


  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 1625 The NORC (1953 RB)" (2017-01-27 last obs.). Jet Propulsion Laboratory. Retrieved 4 June 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1625) The NORC. Springer Berlin Heidelberg. p. 129. ISBN 978-3-540-00238-3. Retrieved 28 December 2016. 
  3. ^ a b c d e f "LCDB Data for (1625) The NORC". Asteroid Lightcurve Database (LCDB). Retrieved 28 December 2016. 
  4. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 28 December 2016. 
  5. ^ a b Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 28 December 2016. 
  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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 28 December 2016. 
  7. ^ a b c d Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522Freely accessible. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 28 December 2016. 
  8. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 28 December 2016. 
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1625) The NORC". Geneva Observatory. Retrieved 28 December 2016. 
  10. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 28 December 2016. 
  11. ^ a b Higgins, David (January 2011). "Period Determination of Asteroid Targets Observed at Hunters Hill Observatory: May 2009 - September 2010". The Minor Planet Bulletin. 38 (1): 41–46. Bibcode:2011MPBu...38...41H. ISSN 1052-8091. Retrieved 28 December 2016. 
  12. ^ a b c Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; et al. (August 2015). "Asteroid Spin-rate Study Using the Intermediate Palomar Transient Factory". The Astrophysical Journal Supplement Series. 219 (2): 19. arXiv:1506.08493Freely accessible. Bibcode:2015ApJS..219...27C. doi:10.1088/0067-0049/219/2/27. Retrieved 28 December 2016. 
  13. ^ a b "1625 The NORC (1953 RB)". Minor Planet Center. Retrieved 28 December 2016. 
  14. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 December 2016. 

External links[edit]