Discovered by L. Boyer MPC designation 1511 Dalera Discovered 22 March 1939 Orbits Sun Discovery site Algiers Observatory | Discovery date 22 March 1939 Minor planet category main-belt · (inner) Absolute magnitude 12.7 Discoverer Louis Boyer Asteroid group Asteroid belt | |
Named after Paul Daléra
(friend of discoverer) Alternative names 1939 FB · 1928 DB
1954 LM People also search for 1339 Désagneauxa, Sun, 1606 Jekhovsky | ||
1511 Daléra, provisional designation 1939 FB, is an asteroid from the inner regions of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 22 March 1939, by French astronomer Louis Boyer at the Algerian Algiers Observatory in North Africa.
Daléra orbits the Sun at a distance of 2.1–2.6 AU once every 3 years and 7 months (1,322 days). Its orbit has an eccentricity of 0.11 and an inclination of 4° with respect to the ecliptic. It was first identified as 1928 DB at Heidelberg Observatory in 1928, extending the body's observation arc by 11 years prior to its official discovery observation.
In March 2015, three rotational light-curves of Daléra were independently obtained by Italian astronomers Maurizio Scardella (D06), Fabio Salvaggio (K54, A81), and Giovanni Casalnuovo (C62) after being reported as a light-curve photometry opportunity at minorplanet.info (CALL). They gave a rotation period of 3.880 and 3.881 hours with a brightness variation of 0.18 and 0.14 magnitude, respectively (U=2/3-/2-). Previously, photometric observations at the Palomar Transient Factory in September 2013, gave a longer period of 4.2227 hours and an amplitude of 0.14 magnitude (U=2).
According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Daléra measures between 11.36 and 18.23 kilometers in diameter, and its surface has an albedo between 0.03 and 0.10. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for S-type asteroids of 0.20 and calculates a diameter of 7.15 kilometers based on an absolute magnitude of 13.09. However, based on the low albedos (0.03, 0.08, 0.10) determined by WISE/NEOWISE, Daléra is not a stony but rather a carbonaceous asteroid, which are uncommon in the inner main-belt.
This minor planet was named after Paul Daléra, a friend of the discovering astronomer Louis Boyer. Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 135)