1511 Daléra

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1511 Daléra
Discovered byL. Boyer
Discovery siteAlgiers Obs.
Discovery date22 March 1939
(1511) Dalera
Named after
Paul Daléra
(friend of discoverer)[2]
1939 FB · 1928 DB
1954 LM
main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc88.75 yr (32,415 days)
Aphelion2.6137 AU
Perihelion2.1022 AU
2.3579 AU
3.62 yr (1,323 days)
0° 16m 19.92s / day
Physical characteristics
Dimensions7.15 km (calculated)[3]
11.36±3.14 km[4]
13.515±0.231 km[5]
18.23±1.28 km[6]
3.880±0.001 h[7][8]
3.881±0.001 h[9]
4.2227±0.0011 h[10]
0.20 (assumed)[3]
12.644±0.002 (R)[10] · 12.70[4][5] · 12.8[1] · 12.99[6] · 13.09[3]

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, North Africa, and named after Paul Daléra, a friend of the discoverer.[2][11]

Classification and orbit[edit]

Daléra orbits the Sun in the inner main-belt at a distance of 2.1–2.6 AU once every 3 years and 7 months (1,323 days). Its orbit has an eccentricity of 0.11 and an inclination of 4° with respect to the ecliptic.[1] 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.[11]

Physical characteristics[edit]

Rotation period[edit]

In March 2015, three rotational lightcurves 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-).[7][8][9] 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).[10]

Diameter and albedo[edit]

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.[4][5][6]

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.[3] 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.[2] The official naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 135)[2]


  1. ^ a b c d "JPL Small-Body Database Browser: 1511 Dalera (1939 FB)" (2016-11-23 last obs.). Jet Propulsion Laboratory. Retrieved 5 June 2017.
  2. ^ a b c d Schmadel, Lutz D. (2007). "(1511) Daléra". Dictionary of Minor Planet Names – (1511) Daléra. Springer Berlin Heidelberg. p. 120. doi:10.1007/978-3-540-29925-7_1512. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1511) Daléra". Asteroid Lightcurve Database (LCDB). Retrieved 4 January 2017.
  4. ^ 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 4 January 2017.
  5. ^ 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:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 4 January 2017.
  6. ^ 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:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 4 January 2017.
  7. ^ a b Scardella, Maurizio; Franceschini, Francesco; Tomassini, Angelo (July 2015). "Rotational Period of 1511 Dalera". The Minor Planet Bulletin. 42 (3): 216. Bibcode:2015MPBu...42Q.216S. ISSN 1052-8091. Retrieved 4 January 2017.
  8. ^ a b Salvaggio, Fabio; Marchini, Alessandro; Franco, Lorenzo (July 2015). "Rotation Period Determination for 1511 Dalera and 2271 Kiso". The Minor Planet Bulletin. 42 (3): 226–227. Bibcode:2015MPBu...42..226S. ISSN 1052-8091. Retrieved 4 January 2017.
  9. ^ a b Casalnuovo, Giovanni Battista (April 2016). "Lightcurve Analysis for Nine Main Belt Asteroids". The Minor Planet Bulletin. 43 (2): 112–115. Bibcode:2016MPBu...43..112C. ISSN 1052-8091. Retrieved 4 January 2017.
  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:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 4 January 2017.
  11. ^ a b "1511 Dalera (1939 FB)". Minor Planet Center. Retrieved 4 January 2017.

External links[edit]