1215 Boyer

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1215 Boyer
Discovery [1]
Discovered by A. Schmitt
Discovery site Algiers Obs.
Discovery date 19 January 1932
MPC designation (1215) Boyer
Named after
Louis Boyer
(French astronomer)[2]
1932 BA
main-belt · (middle)
Eunomia[3] · Maria[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 85.46 yr (31,214 days)
Aphelion 2.9213 AU
Perihelion 2.2352 AU
2.5783 AU
Eccentricity 0.1331
4.14 yr (1,512 days)
0° 14m 17.16s / day
Inclination 15.915°
Physical characteristics
Dimensions 13.041±0.106 km[5]
14.705±0.091 km[6]
17.47 km (calculated)[3]
20.68±0.79 km[7]
23.06±4.95 km[8]
24.65±0.36 km[9]
10.36±0.05 h[4]
0.21 (assumed)[3]
Tholen = S[1] · S[3]
B–V = 0.900[1]
U–B = 0.459[1]

1215 Boyer, provisional designation 1932 BA, is a stony Eunomian asteroid from the central region of the asteroid belt, approximately 20 kilometers in diameter. It was discovered by astronomer Alfred Schmitt in 1932, who named it after French astronomer and college Louis Boyer.[11]


Boyer was discovered on 19 January 1932, by French astronomer Alfred Schmitt at the Algiers Observatory in Algeria, North Africa.[1] Eight days later, it was independently discovered by Karl Reinmuth at Heidelberg Observatory in Germany.[2] The body's observation arc begins at Algiers with its official discovery observation.[11]

Classification and orbit[edit]

Boyer is a member of the Eunomia family (502), the most prominent family in the intermediate main-belt, which mostly consists of stony asteroids. Conversely, Boyer has also been grouped into the Maria family (506).[4]

It orbits the Sun at a distance of 2.2–2.9 AU once every 4 years and 2 months (1,512 days). Its orbit has an eccentricity of 0.13 and an inclination of 16° with respect to the ecliptic.[1]

Physical characteristics[edit]

In the Tholen classification, Boyer is a common, stony S-type asteroid.[1]


In August 2008 and May 2012, two rotational lightcurves of Boyer were obtained from photometric observations by an international collaboration of astronomers studying the rotational properties of Maria asteroids, using the ground-based Wise Observatory in Israel. Lightcurve analysis gave a rotation period of 10.36 hours with a brightness variation of 0.31 and 050 magnitude, respectively (U=2-/2).[4]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Boyer measures between 13.041 and 24.65 kilometers in diameter and its surface has an albedo between 0.116 and 0.3012.[5][6][7][8][9]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21, derived from the Eunomia family's largest member and namesake, 15 Eunomia, and calculates a diameter of 17.47 kilometers with an absolute magnitude of 11.1.[3]


This minor planet was named by the discoverer after his colleague at Algiers Observatory, Louis Boyer (1901–1999), who worked extensively on asteroids and comets. Boyer himself was a discoverer of minor planets at Algiers. He later worked on identifications at Nice observatory.[2] The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 4418).[12]


  1. ^ a b c d e f g h i "JPL Small-Body Database Browser: 1215 Boyer (1932 BA)" (2017-07-05 last obs.). Jet Propulsion Laboratory. Retrieved 17 August 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1215) Boyer. Springer Berlin Heidelberg. p. 101. ISBN 978-3-540-00238-3. Retrieved 17 August 2017.
  3. ^ a b c d e f "LCDB Data for (1215) Boyer". Asteroid Lightcurve Database (LCDB). Retrieved 17 August 2017.
  4. ^ a b c d Kim, M.-J.; Choi, Y.-J.; Moon, H.-K.; Byun, Y.-I.; Brosch, N.; Kaplan, M.; et al. (March 2014). "Rotational Properties of the Maria Asteroid Family" (PDF). The Astronomical Journal. 147 (3): 15. arXiv:1311.5318. Bibcode:2014AJ....147...56K. doi:10.1088/0004-6256/147/3/56. Retrieved 17 August 2017.
  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:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 17 August 2017.
  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:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 17 August 2017.
  7. ^ 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 17 August 2017.
  8. ^ 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 17 August 2017.
  9. ^ 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 17 August 2017.
  10. ^ 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 17 August 2017.
  11. ^ a b "1215 Boyer (1932 BA)". Minor Planet Center. Retrieved 17 August 2017.
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 August 2017.

External links[edit]