988 Appella

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988 Appella
Discovery [1]
Discovered by B. Jekhovsky
Discovery site Algiers Observatory
Discovery date 10 November 1922
MPC designation 988 Appella
Named after
Paul Appell
1922 MT · 1955 QJ1
main-belt · Themis[3]
Orbital characteristics[1]
Epoch 27 June 2015 (JD 2457200.5)
Uncertainty parameter 0
Observation arc 75.50 yr (27,577 days)      
Aphelion 3.8814 AU
Perihelion 2.4013 AU
3.1414 AU
Eccentricity 0.2355
5.57 yr (2,034 days)
Inclination 1.5750°
Physical characteristics
Dimensions 25.91±1.2 km (IRAS:18)[4]
30.09±0.37 km[5]
20.431±0.215 km[6]
20.44±0.33 km[7]
22±2 km[8]
25.80 km (derived)[3]
120 h[9]
7.0±1.0 h[10]
0.0871±0.009 (IRAS:18)[4]
0.0667 (derived)[3]

988 Appella, provisional designation 1922 MT, is a dark Themistian asteroid and slow rotator from the outer region of the asteroid belt, about 26 kilometers in diameter. It was discovered by Russian–French astronomer Benjamin Jekhowsky at Algiers Observatory in Algeria, North Africa, on 10 November 1922.[11]

The asteroid is a member of the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. It orbits the Sun at a distance of 2.4–3.9 AU once every 5 years and 7 months (2,034 days). Its orbit is tilted by 2 degrees to the plane of the ecliptic and shows an eccentricity of 0.24.[1] In 2012, a photometric light-curve analysis at the U.S. Santana Observatory in California (646) gave a long rotation period of 120 hours with a brightness amplitude of 0.4 in magnitude,[9] rendering a tentative 2006-observation by Italian astronomers Roberto Crippa and Federico Manzini obsolete.[10]

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the U.S. Wide-field Infrared Survey Explorer with its NEOWISE mission, the asteroid's surface has an albedo in the range of 0.07 to 0.14.[4][5][6][7] Although the Collaborative Asteroid Lightcurve Link (CALL) derives a low albedo in accordance with the space-based surveys, CALL classifies the dark Themistian body as a stony S-type rather than a carbonaceous C-type asteroid.[3]

The minor planet was named in honor of French mathematician Paul Émile Appel (1855–1930), president of the Academy of Sciences and of the Société Astronomique de France, and the author of Traité de Mécanique Rationelle published in 1893.[2][12]


  1. ^ a b c d "JPL Small-Body Database Browser: 988 Appella (1922 MT)" (2015-05-24 last obs.). Jet Propulsion Laboratory. Retrieved January 2016. 
  2. ^ a b Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (988) Appella. Springer Berlin Heidelberg. p. 86. ISBN 978-3-540-29925-7. Retrieved January 2016. 
  3. ^ a b c d e "LCDB Data for (988) Appella". Asteroid Lightcurve Database (LCDB). Retrieved January 2016. 
  4. ^ a b c 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 January 2016. 
  5. ^ a b c 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 January 2016. 
  6. ^ a b c Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal 741 (2): 25. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved January 2016. 
  7. ^ a b c 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. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved January 2016. 
  8. ^ a b Alí-Lagoa, V.; de León, J.; Licandro, J.; Delbó, M.; Campins, H.; Pinilla-Alonso, N.; et al. (June 2013). "Physical properties of B-type asteroids from WISE data". Astronomy and Astrophysics 554: 16. Bibcode:2013A&A...554A..71A. doi:10.1051/0004-6361/201220680. Retrieved January 2016. 
  9. ^ a b Stephens, Robert D. (April 2013). "Asteroids Observed from Santana and CS3 Observatories: 2012 October - December". Bulletin of the Minor Planets (Section of the Association of Lunar and Planetary Observers) 40 (2): 92. Bibcode:2013MPBu...40...92S. ISSN 1052-8091. Retrieved January 2016. 
  10. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (988) Appella". Geneva Observatory. Retrieved January 2016. 
  11. ^ "988 Appella (1922 MT)". Minor Planet Center. Retrieved January 2016. 
  12. ^ "Internet Archive – Traité de Mécanique Rationelle". Paris, Gauthier-Villars et cie. Retrieved January 2016. 

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