988 Appella

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988 Appella
Discovery [1]
Discovered byB. Jekhovsky
Discovery siteAlgiers Obs.
Discovery date10 November 1922
MPC designation(988) Appella
Named after
Paul Appell
(French mathematician)[2]
1922 MT · 1955 QJ1
main-belt · Themis[3]
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc76.56 yr (27,964 days)
Aphelion3.8829 AU
Perihelion2.4017 AU
3.1423 AU
5.57 yr (2,035 days)
0° 10m 36.84s / day
Physical characteristics
Dimensions20.431±0.215 km[4][5]
20.44±0.33 km[6]
21.7±2.2 km[7]
22±2 km[8]
25.77 km (derived)[3]
25.91±1.2 km (IRAS:18)[9]
30.09±0.37 km[10]
7.0±1.0 h (dated)[11]
120 h[12]
0.0609 (derived)[3]
0.0871±0.009 (IRAS:18)[9]
11.2[4][9][10] · 11.50[7] · 11.50±0.27[13] · 11.60[1][3][6][8]

988 Appella, provisional designation 1922 MT, is a dark Themistian asteroid and slow rotator from the outer region of the asteroid belt, approximately 26 kilometers in diameter. It was discovered on 10 November 1922, by Russian–French astronomer Benjamin Jekhowsky at Algiers Observatory in Algeria, North Africa.[14] The asteroid was later named after French mathematician Paul Émile Appel.[2]

Classification and orbit[edit]

Appella 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 (2,035 days). Its orbit has an eccentricity of 0.24 and an inclination of 2° with respect to the ecliptic.[1]

The Minor Planet Center's first recorded astrometric observation is from Simeiz Observatory in 1933. The body's observation arc begins at Uccle Observatory in 1939, or 17 years after its official discovery observation at Algiers.[14]

Physical characteristics[edit]

In 2012, a rotational lightcurve of Appella was obtained from photometric observations by American astronomer Robert Stephens at the Santana Observatory (646) in California. It gave a long rotation period of 120 hours with a brightness amplitude of 0.4 in magnitude,[12] rendering a tentative 2006-observation by Italian astronomers Roberto Crippa and Federico Manzini obsolete.[11] This makes Appella one of a few hundreds slow rotator with a period above 100 hours.

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its NEOWISE mission, Appella measures between 20.431 and 30.09 kilometers in diameter, and its surface has an albedo from 0.066 to 0.1401.[4][6][7][8][9][10]

The Collaborative Asteroid Lightcurve Link (CALL) derives an albedo of 0.0609 and a diameter of 25.77 kilometers with an absolute magnitude of 11.60. Although the figures are in accordance with the space-based surveys, CALL classifies Appella as a stony S-type rather than a carbonaceous C-type asteroid.[3]


This 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][15] The official naming citation was first published by Paul Herget in The Names of the Minor Planets in 1955 (H 94).[2]


  1. ^ a b c d "JPL Small-Body Database Browser: 988 Appella (1922 MT)" (2016-06-14 last obs.). Jet Propulsion Laboratory. Retrieved 13 February 2017.
  2. ^ a b c d Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (988) Appella. Springer Berlin Heidelberg. p. 86. ISBN 978-3-540-00238-3. Retrieved 13 February 2017.
  3. ^ a b c d e f "LCDB Data for (988) Appella". Asteroid Lightcurve Database (LCDB). Retrieved 13 February 2017.
  4. ^ 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 13 February 2017.
  5. ^ a b Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 13 February 2017.
  6. ^ 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 13 February 2017.
  7. ^ a b c d Alí-Lagoa, V.; Licandro, J.; Gil-Hutton, R.; Cañ; ada-Assandri, M.; Delbo', M.; et al. (June 2016). "Differences between the Pallas collisional family and similarly sized B-type asteroids". Astronomy and Astrophysics. 591: 11. Bibcode:2016A&A...591A..14A. doi:10.1051/0004-6361/201527660. Retrieved 13 February 2017.
  8. ^ a b c d 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. arXiv:1303.5487. Bibcode:2013A&A...554A..71A. doi:10.1051/0004-6361/201220680. Retrieved 13 February 2017.
  9. ^ a b c d 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 13 February 2017.
  10. ^ 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 13 February 2017.
  11. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (988) Appella". Geneva Observatory. Retrieved 13 February 2017.
  12. ^ a b Stephens, Robert D. (April 2013). "Asteroids Observed from Santana and CS3 Observatories: 2012 October - December". The Minor Planet Bulletin. 40 (2): 92. Bibcode:2013MPBu...40...92S. ISSN 1052-8091. Retrieved 13 February 2017.
  13. ^ 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 13 February 2017.
  14. ^ a b "988 Appella (1922 MT)". Minor Planet Center. Retrieved 13 February 2017.
  15. ^ "Internet Archive – Traité de Mécanique Rationelle". Paris, Gauthier-Villars et cie. Retrieved 11 January 2016.

External links[edit]