1319 Disa

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1319 Disa
Discovery [1]
Discovered by C. Jackson
Discovery site Johannesburg Obs.
Discovery date 19 March 1934
MPC designation (1319) Disa
Named after
Disa (orchidflowering plant)[2]
1934 FO · 1929 GE
1970 FM · A908 EA
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 108.19 yr (39,516 days)
Aphelion 3.6051 AU
Perihelion 2.3685 AU
2.9868 AU
Eccentricity 0.2070
5.16 yr (1,885 days)
0° 11m 27.24s / day
Inclination 2.7999°
Physical characteristics
Dimensions 16.88±1.12 km[4]
24.00±0.37 km[5]
25.651±0.321 km[6]
25.894±0.180 km[7]
40.33 km (calculated)[3]
7.080±0.003 h[8]
7.0820±0.0077 h[9]
7.082±0.001 h[10]
0.057 (assumed)[3]
P[7] · C[3]
10.391±0.002 (R)[9] · 10.50[4] · 10.7[1][3] · 11.1[5][7]

1319 Disa, provisional designation 1934 FO, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 25 kilometers in diameter. It was discovered on 19 March 1934, by English-born, South African astronomer Cyril Jackson at Johannesburg Observatory in South Africa.[11] It is named for the orchid Disa.[2]


Disa orbits the Sun at a distance of 2.4–3.6 AU once every 5 years and 2 months (1,885 days). Its orbit has an eccentricity of 0.21 and an inclination of 3° with respect to the ecliptic.[1] It was first identified as A908 EA at Heidelberg Observatory in 1908. The body's observation arc begins in 1929, when it was identified as 1929 GE at the discovering observatory, 6 years prior to its official discovery observation.[11]

Rotation period[edit]

A rotational lightcurve of Disa was obtained by American astronomer Brian D. Warner at his Palmer Divide Observatory in March 2006, and by French amateur astronomer Pierre Antonini in February 2011, respectively. Analysis of both light-curves gave a well-defined rotation period of 7.08 hours with a brightness variation of 0.26 and 0.27 magnitude (U=3/3).[8][10] In September 2013, photometric observations in the R-band at the Palomar Transient Factory gave a concurring light-curve of 7.082 hours and an amplitude of 0.24 magnitude (U=2).[9]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite, and the 2014-results by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Disa measures 24.00 and 25.65 kilometers in diameter, and its surface has an albedo of 0.116 and 0.097, respectively.[5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous C-type asteroids of 0.057 and calculates a diameter of 40.33 kilometers using an absolute magnitude of 10.7.[3] Preliminary results by NEOWISE also classified the body as a reddish P-type asteroid.[7]


This minor planet was named after Disa, also known as "African weed-orchid", a large genus of more than a hundred tropical orchids, common in southern Africa.[2] In 1955, this naming citation was first published by Paul Herget in The Names of the Minor Planets (H 120).[2]


  1. ^ a b c d "JPL Small-Body Database Browser: 1319 Disa (1934 FO)" (2016-06-01 last obs.). Jet Propulsion Laboratory. Retrieved 16 January 2017. 
  2. ^ a b c d Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1319) Disa. Springer Berlin Heidelberg. p. 108. ISBN 978-3-540-00238-3. Retrieved 16 January 2017. 
  3. ^ a b c d e f "LCDB Data for (1319) Disa". Asteroid Lightcurve Database (LCDB). Retrieved 16 January 2017. 
  4. ^ 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. arXiv:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 16 January 2017. 
  5. ^ 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" (PDF). Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 16 January 2017. 
  6. ^ 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:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 16 January 2017. 
  7. ^ a b c d e 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 16 January 2017. 
  8. ^ a b Warner, Brian D. (December 2006). "Asteroid lightcurve analysis at the Palmer Divide Observatory - February - March 2006". The Minor Planet Bulletin. 33 (4): 82–84. Bibcode:2006MPBu...33...82W. ISSN 1052-8091. Retrieved 16 January 2017. 
  9. ^ 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:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 16 January 2017. 
  10. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1319) Disa". Geneva Observatory. Retrieved 16 January 2017. 
  11. ^ a b "1319 Disa (1934 FO)". Minor Planet Center. Retrieved 16 January 2017. 

External links[edit]