2145 Blaauw

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2145 Blaauw
Discovery [1]
Discovered byR. M. West
Discovery siteLa Silla Obs.
Discovery date24 October 1976
MPC designation(2145) Blaauw
Named after
Adriaan Blaauw[2]
(Dutch astronomer)
1976 UF · 1929 XS
1963 RK · 1980 TW
main-belt · (outer)[1][3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc41.02 yr (14,983 days)
Aphelion3.5269 AU
Perihelion2.9059 AU
3.2164 AU
5.77 yr (2,107 days)
0° 10m 15.24s / day
Physical characteristics
Dimensions34.06 km (derived)[3]
37.11±0.53 km[5]
38.00±10.68 km[6]
40.549±0.848 km[7]
40.55±0.85 km[7]
12.141±0.003 h[8]
0.0665 (derived)[3]
C (assumed)[3]
10.60[5] · 10.80[6][7] · 10.83±0.34[9] · 10.9[1][3]

2145 Blaauw, provisional designation 1976 UF, is a dark Ursula asteroid from the outer regions of the asteroid belt, approximately 38 kilometers in diameter. It was discovered on 24 October 1976, by astronomer Richard Martin West at the La Silla Observatory in northern Chile.[10] The asteroid was named after Dutch astronomer Adriaan Blaauw.[2]

Orbit and classification[edit]

Blaauw is a member of the Ursula family (631),[4] a large family of C- and X-type asteroids, named after its parent body, 375 Ursula.[11] It orbits the Sun in the outer asteroid belt at a distance of 2.9–3.5 AU once every 5 years and 9 months (2,107 days; semi-major axis of 3.22 AU). Its orbit has an eccentricity of 0.10 and an inclination of 15° with respect to the ecliptic.[1]

The asteroid was first identified as 1929 XS at Lowell Observatory in December 1929. The body's observation arc begins with its identification as 1963 RK at the Karl Schwarzschild Observatory in September 1963, or 13 years prior to its official discovery observation at La Silla.[10]

Physical characteristics[edit]

Blaauw is an assumed, carbonaceous C-type asteroid.[3]

Rotation period[edit]

Photometric measurements made from the Oakley Southern Sky Observatory during 2012 gave a lightcurve with a period of 12.141 ± 0.003 hours and a variation in brightness of 0.18 ± 0.03 in magnitude (U=2+).[8]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Blaauw measures between 37.11 and 40.55 kilometers in diameter and its surface has an albedo between 0.051 and 0.076.[5][6][7]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0665 and a diameter of 34.06 kilometers based on an absolute magnitude of 10.9.[3]


This minor planet was named after Dutch astronomer Adriaan Blaauw (1914–2010), who was director of the European Southern Observatory (1970–74), president of the International Astronomical Union (1976–79) and professor at the Leiden Observatory (1975–1981). His study included the structure of the Milky Way and stellar kinematics and associations.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 4788).[12]


  1. ^ a b c d e "JPL Small-Body Database Browser: 2145 Blaauw (1976 UF)" (2017-11-01 last obs.). Jet Propulsion Laboratory. Retrieved 6 December 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(2145) Blaauw". Dictionary of Minor Planet Names – (2145) Blaauw. Springer Berlin Heidelberg. p. 174. doi:10.1007/978-3-540-29925-7_2146. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g "LCDB Data for (2145) Blaauw". Asteroid Lightcurve Database (LCDB). Retrieved 6 December 2017.
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 6 December 2017.
  5. ^ 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 6 December 2017.
  6. ^ 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:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 6 December 2017.
  7. ^ a b c d e 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:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 6 December 2017.
  8. ^ a b Moravec, Patricia; Cochren, Joseph; Gerhardt, Michael; Harris, Andrew; Karnemaat, Ryan; Melton, Elizabeth; et al. (October 2012). "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2012 January-April". The Minor Planet Bulletin. 39 (4): 213–216. Bibcode:2012MPBu...39..213M. ISSN 1052-8091. Retrieved 6 December 2017.
  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:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 6 December 2017.
  10. ^ a b "2145 Blaauw (1976 UF)". Minor Planet Center. Retrieved 6 December 2017.
  11. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 6 December 2017.

External links[edit]