1138 Attica

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
1138 Attica
Discovery [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date 22 November 1929
MPC designation (1138) Attica
Named after
Attica Province
(province of Greece)[2]
1929 WF · 1954 GK
main-belt · (outer)
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 86.52 yr (31,600 days)
Aphelion 3.3801 AU
Perihelion 2.9104 AU
3.1453 AU
Eccentricity 0.0747
5.58 yr (2,037 days)
0° 10m 36.12s / day
Inclination 13.971°
Physical characteristics
Dimensions 23.681±0.113 km[3]
30±2 km (generic)[4]

1138 Attica, provisional designation 1929 WF, is an asteroid from the outer region of the asteroid belt, approximately 24 kilometers in diameter. It was discovered on 22 November 1929, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany.[6] It was named after the Attica Province in Greece.[2]

Orbit and classification[edit]

Attica orbits the Sun in the outer main-belt at a distance of 2.9–3.4 AU once every 5 years and 7 months (2,037 days). Its orbit has an eccentricity of 0.07 and an inclination of 14° with respect to the ecliptic.[1] The body's observation arc begins at Heidelberg with its official discovery observation. No precoveries were taken, and no prior identifications were made.[6]

Physical characteristics[edit]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Attica measures 23.681 kilometers in diameter and its surface has an albedo of 0.105.[3] Based on a generic magnitude-to-diameter conversion, its diameter is between 13 and 32 kilometer for an absolute magnitude of 11.4 and an assumed albedo in the range of 0.05 to 0.25.[4] Since asteroids in the outer main-belt are typically of carbonaceous rather than stony composition, with averaged standard albedos of 0.057, Attica's diameter can be estimated to measure close to 30 kilometers, as the lower a body's albedo (reflectivity), the larger its diameter at a fixed absolute magnitude (brightness).[4]

As of 2017, Attica's spectral type, as well as its rotation period and shape remain unknown.[1][5] This is rather unusual, as both spectral type and rotation period have been determined for most larger and low-numbered asteroids (also see minor-planet lists from 1 up to 2000).


This minor planet is named after the province of Attica in eastern Greece with the capital Athens.[2] Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 102).[2]


  1. ^ a b c d e "JPL Small-Body Database Browser: 1138 Attica (1929 WF)" (2016-05-29 last obs.). Jet Propulsion Laboratory. Retrieved 8 February 2017. 
  2. ^ a b c d Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1138) Attica. Springer Berlin Heidelberg. p. 96. ISBN 978-3-540-00238-3. Retrieved 8 February 2017. 
  3. ^ a b c 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 8 February 2017. 
  4. ^ a b c "Absolute Magnitude (H)". NASA/JPL. Retrieved 8 February 2017. 
  5. ^ a b "LCDB Data for (1138) Attica". Asteroid Lightcurve Database (LCDB). Retrieved 8 February 2017. 
  6. ^ a b "1138 Attica (1929 WF)". Minor Planet Center. Retrieved 8 February 2017. 

External links[edit]