1212 Francette

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1212 Francette
Discovery [1]
Discovered by L. Boyer
Discovery site Algiers Obs.
Discovery date 3 December 1931
MPC designation (1212) Francette
Named after
Francette Boyer [2]
(discoverer's wife)
1931 XC · 1949 HB1
1949 HZ · 1965 JB
A918 KA
main-belt · (outer)[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 85.98 yr (31,406 days)
Aphelion 4.7109 AU
Perihelion 3.1972 AU
3.9541 AU
Eccentricity 0.1914
7.86 yr (2,872 days)
0° 7m 31.44s / day
Inclination 7.5898°
Jupiter MOID 0.3433 AU
Physical characteristics
Dimensions 76.395±0.155 km[5]
82.13±3.2 km[6]
85.81±2.18 km[7]
16 h (poor)[8]
22.433±0.007 h[9][a]
Tholen = P[1] · P[10]
SMASS = X[1][3]
B–V = 0.693[1]
U–B = 0.215[1]
9.54[1][3][6][7] · 9.62±0.23[11]

1212 Francette, provisional designation 1931 XC, is a dark Hildian asteroid from the outermost regions of the asteroid belt, approximately 82 kilometers in diameter. It was discovered on 3 December 1931, by French astronomer Louis Boyer at the Algiers Observatory in Algeria, North Africa, who named it after his wife Francette Boyer.[2][12]

Orbit and classification[edit]

Francette is a member of the small Hilda family (001),[4] an asteroid family within the dynamical Hilda group,[3] that stays in an orbital resonance with the gas giant Jupiter. It orbits the Sun in the outermost asteroid belt at a distance of 3.2–4.7 AU once every 7 years and 10 months (2,872 days; semi-major axis of 3.95 AU). Its orbit has an eccentricity of 0.19 and an inclination of 8° with respect to the ecliptic.[1]

The asteroid was first observed as A918 KA at Simeiz Observatory in May 1918. The body's observation arc begins at Algiers with its official discovery observation.[12]

Physical characteristics[edit]

In the Tholen classification, Francette is a primitive P-type asteroid.[1] In the SMASS classification it is an X-type asteroid.[1][3] The Wide-field Infrared Survey Explorer (WISE) also characterizes Francette as a dark P-type,[10] while the overall spectral type for members of the Hilda family is typically that of a carbonaceous C-type.[13]:23

Rotation period[edit]

In July 2016, a rotational lightcurve of Francette was obtained from photometric observations by American astronomers Brian Warner, Robert Stephens and Dan Coley at the Center for Solar System Studies (U80–82) in California. Lightcurve analysis gave a rotation period of 22.433 hours with a brightness variation of 0.13 magnitude (U=2/3-), superseding a period of 16 hours, previously measured in the 1970s.[8][9][a]

Diameter and albedo[edit]

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's WISE telescope, Francette measures between 76.395 and 85.81 kilometers in diameter and its surface has an albedo between 0.037 and 0.046.[5][6][7][10]

The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0400 and a diameter of 82.13 kilometers based on an absolute magnitude of 9.54.[3][6]


This minor planet was named by the discoverer after his wife, Francette Boyer. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 112).[2]


  1. ^ a b Lightcurve plot of (1212) Francette by Warner, Stephens and Coley at the CS3 from 5 July to 2 August 2016 rotation period 22.433±0.007 hours and an amplitude of 0.13 mag. Quality code of 3-. Summary figures at the LCDB


  1. ^ a b c d e f g h i j k "JPL Small-Body Database Browser: 1212 Francette (1931 XC)" (2017-11-27 last obs.). Jet Propulsion Laboratory. Retrieved 5 January 2018. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1212) Francette. Springer Berlin Heidelberg. p. 101. ISBN 978-3-540-00238-3. Retrieved 5 January 2018. 
  3. ^ a b c d e f "LCDB Data for (1212) Francette". Asteroid Lightcurve Database (LCDB). Retrieved 5 January 2018. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 5 January 2018. 
  5. ^ a b c Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Spahr, T.; McMillan, R. S.; et al. (January 2012). "WISE/NEOWISE Observations of the Hilda Population: Preliminary Results". The Astrophysical Journal. 744 (2): 15. arXiv:1110.0283Freely accessible. Bibcode:2012ApJ...744..197G. doi:10.1088/0004-637X/744/2/197. Retrieved 5 January 2018. 
  6. ^ a b c d e Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. Bibcode:2004PDSS...12.....T. Retrieved 5 January 2018. 
  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 5 January 2018. 
  8. ^ a b Taylor, R. C.; Gehrels, T.; Capen, R. C. (September 1976). "Minor planets and related objects. XXI – Photometry of eight asteroids". Astronomical Journal: 778–786.NASA–supportedresearch. Bibcode:1976AJ.....81..778T. doi:10.1086/111953. Retrieved 5 January 2018. 
  9. ^ a b Warner, Brian D.; Stephens, Robert D.; Coley, Daniel A. (January 2017). "Lightcurve Analysis of Hilda Asteroids at the Center for Solar System Studies: 2016 June-September". The Minor Planet Bulletin. 44 (1): 36–41. Bibcode:2017MPBu...44...36W. ISSN 1052-8091. Retrieved 5 January 2018. 
  10. ^ 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:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 5 January 2018. 
  11. ^ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 5 January 2018. 
  12. ^ a b "1212 Francette (1931 XC)". Minor Planet Center. Retrieved 5 January 2018. 
  13. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families" (PDF). Asteroids IV: 297–321. arXiv:1502.01628Freely accessible. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. Retrieved 5 January 2018. 

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