1241 Dysona

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1241 Dysona
1241Dysona (Lightcurve Inversion).png
Lightcurve-based 3D-model of Dysona
Discovery [1]
Discovered by H. E. Wood
Discovery site Johannesburg Obs.
Discovery date 4 March 1932
MPC designation (1241) Dysona
Named after
Frank Watson Dyson[2]
(English astronomer)
1932 EB1 · 1931 AA1
1945 RA · 1948 CE
1956 PB · A908 DC
A920 EB
main-belt · (outer)[3]
background [4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 97.31 yr (35,542 days)
Aphelion 3.5165 AU
Perihelion 2.8633 AU
3.1899 AU
Eccentricity 0.1024
5.70 yr (2,081 days)
0° 10m 22.8s / day
Inclination 23.518°
Physical characteristics
Dimensions 70.757±0.287 km[5]
74.83±28.44 km[6]
75.62±0.82 km[7]
77.14±0.86 km[8]
77.47±26.72 km[9]
79.190±0.694 km[10]
83.05±4.4 km[11]
8.355±0.001 h[12]
8.60738 h[13]
8.6080±0.0005 h[14]
Tholen = PDC [1][3]
B–V = 0.750[1]
U–B = 0.290[1]
9.45[1][3][5][6][7][8][11] · 9.74[9]

1241 Dysona, provisional designation 1932 EB1, is a dark background asteroid from the outer regions of the asteroid belt, approximately 77 kilometers in diameter. It was discovered on 4 March 1932, by English astronomer Harry Edwin Wood at the Union Observatory in Johannesburg, South Africa.[15] The asteroid was named after English astronomer Frank Watson Dyson.[2]

Orbit and classification[edit]

Dysona is a non-family asteroid from the main belt's background population.[4] It orbits the Sun in the outer main-belt at a distance of 2.9–3.5 AU once every 5 years and 8 months (2,081 days; semi-major axis of 3.19 AU). Its orbit has an eccentricity of 0.10 and an inclination of 24° with respect to the ecliptic.[1]

The asteroid was first observed as A908 DC at Taunton Observatory (803) in February 1908. The body's observation arc begins with its observations as A920 EB at Heidelberg Observatory in March 1920, or 12 years prior to its official discovery observation at Johannesburg.[15]

Physical characteristics[edit]

In the Tholen classification, Dysona's spectral type is ambiguous, closest to a primitive P-type and somewhat similar to a D- and C-type asteroid (PDC).[1][3]

Rotation period and pole[edit]

In April 2006, a rotational lightcurve of Dysona was obtained by Julian Oey at Leura Observatory (E17) in Australia. Lightcurve analysis gave a rotation period of 8.6080 hours with a brightness variation of 0.24 magnitude (U=3-),[14] superseding photometric observations by Jean-Gabriel Bosch and Laurent Brunetto in October 2010, who measured a period of 8.355 hours and an amplitude of 0.25 magnitude (U=2).[12]

In 2016, a modeled lightcurve using data from UAPC, the Palomar Transient Factory survey, and individual observers, gave a concurring period of 8.60738 hours as well an astronomical pole of (125.0°, −68.0°) in ecliptic coordinates (λ, β).[13]

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 Wide-field Infrared Survey Explorer, Dysona measures between 70.757 and 83.05 kilometers in diameter and its surface has an albedo between 0.04 and 0.0585.[5][6][7][8][9][10][11]

The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0425 and a diameter of 83.05 kilometers based on an absolute magnitude of 9.45.[3]


This minor planet was named after English astronomer Frank Watson Dyson (1868–1939), Astronomer Royal of England, director of the Royal Observatory, Greenwich, awarded the Bruce Medal in 1922, and president of the International Astronomical Union from 1928 to 1932. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 114). The lunar crater Dyson was also named in his honor.[2]


  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 1241 Dysona (1932 EB1)" (2017-07-01 last obs.). Jet Propulsion Laboratory. Retrieved 4 January 2018.
  2. ^ a b c Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (1241) Dysona. Springer Berlin Heidelberg. p. 103. ISBN 978-3-540-00238-3. Retrieved 4 January 2018.
  3. ^ a b c d e "LCDB Data for (1241) Dysona". Asteroid Lightcurve Database (LCDB). Retrieved 4 January 2018.
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 4 January 2018.
  5. ^ 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 4 January 2018.
  6. ^ 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 4 January 2018.
  7. ^ 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 4 January 2018.
  8. ^ 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 4 January 2018.
  9. ^ a b c d Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 4 January 2018.
  10. ^ a b c 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" (PDF). The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 4 January 2018.
  11. ^ 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. Archived from the original on 2016-06-03. Retrieved 4 January 2018.
  12. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1241) Dysona". Geneva Observatory. Retrieved 4 January 2018.
  13. ^ a b Hanus, J.; Durech, J.; Broz, M.; Marciniak, A.; Warner, B. D.; Pilcher, F.; et al. (March 2013). "Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution" (PDF). Astronomy and Astrophysics. 551: 16. arXiv:1301.6943. Bibcode:2013A&A...551A..67H. doi:10.1051/0004-6361/201220701. Retrieved 26 September 2017.
  14. ^ a b Oey, Julian; Vilagi, J.; Gajdos, S.; Kornos, L.; Galad, A. (September 2007). "Light curve Analysis of 8 Asteroids from Leura and Other Collaborating Observatories". The Minor Planet Bulletin. 34 (3): 81–83. Bibcode:2007MPBu...34...81O. ISSN 1052-8091. Retrieved 4 January 2018.
  15. ^ a b "1241 Dysona (1932 EB1)". Minor Planet Center. Retrieved 4 January 2018.

External links[edit]