1227 Geranium

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1227 Geranium
Discovery [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date 5 October 1931
MPC designation (1227) Geranium
Named after
(flowering plant)
1931 TD · 1934 CL1
main-belt · (outer)[1][3]
background [4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 86.14 yr (31,463 d)
Aphelion 3.8358 AU
Perihelion 2.6018 AU
3.2188 AU
Eccentricity 0.1917
5.77 yr (2,109 days)
0° 10m 14.52s / day
Inclination 16.492°
Physical characteristics
Dimensions 41.46 km (derived)[3]
46.08±0.80 km[5]
46.269±0.140 km[6]
51.025±0.535 km[7]
12.363±0.004 h[8]
0.0492 (derived)[3]
10.10[5][7] · 10.8[1][3]

1227 Geranium, provisional designation 1931 TD, is a carbonaceous background asteroid from the outer regions of the asteroid belt, approximately 46 kilometers in diameter. It was discovered on 5 October 1931, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory.[9] The asteroid was named for the flowering plant Geranium (cranesbills).[2]

Orbit and classification[edit]

Geranium 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 2.6–3.8 AU once every 5 years and 9 months (2,109 days; semi-major axis 3.22 AU). Its orbit has an eccentricity of 0.19 and an inclination of 16° with respect to the ecliptic.[1]

The body's observation arc begins at Uccle Observatory, four days after its official discovery observation at Heidelberg.[9]

Physical characteristics[edit]

Geranium has been characterized as a carbonaceous C-type asteroid by SDSS–MFB (Masi Foglia Bus).[3]

Rotation period[edit]

In April 2010, a rotational lightcurve of Geranium was obtained from photometric observations by astronomers at the Oakley Southern Sky Observatory in Australia. Lightcurve analysis gave a well-defined rotation period of 12.363 hours with a brightness amplitude of 0.08 magnitude, indicative for a rather spherical shape (U=3).[8]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Geranium measures between 46.08 and 51.025 kilometers in diameter and its surface has an albedo between 0.0619 and 0.076.[5][6][7]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0492 and a diameter of 41.46 kilometers based on an absolute magnitude of 10.8.[3]


This minor planet was named after Geranium, a genus of flowering plants commonly known as "cranesbills". The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 113).[2]


The initials of the minor planets (1227) through (1234), all discovered by Reinmuth, spell out "G. Stracke". Gustav Stracke was a German astronomer and orbit computer, who had asked that no planet be named after him. In this manner Reinmuth was able to honour the man whilst honoring his wish. Nevertheless, Reinmuth directly honored Stracke by naming planet 1019 Strackea later on.[10] The astronomer Brian Marsden was honored by the same type of meta-naming using consecutive initial letters in 1995, spelling out "Brian M." in the sequence of minor planets (5694) through (5699).[10]

Reinmuth's flowers[edit]

Due to his many discoveries, Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between (1009) and (1200). This list also contained a sequence of 28 asteroids, starting with 1054 Forsytia, that were all named after plants, in particular flowering plants (also see list of minor planets named after animals and plants).[11]


  1. ^ a b c d e "JPL Small-Body Database Browser: 1227 Geranium (1931 TD)" (2017-11-25 last obs.). Jet Propulsion Laboratory. Retrieved 9 January 2018. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1227) Geranium. Springer Berlin Heidelberg. p. 102. ISBN 978-3-540-00238-3. Retrieved 9 January 2018. 
  3. ^ a b c d e f g "LCDB Data for (1227) Geranium". Asteroid Lightcurve Database (LCDB). Retrieved 9 January 2018. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 9 January 2018. 
  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". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 9 January 2018. 
  6. ^ 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:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 9 January 2018. 
  7. ^ 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 9 January 2018. 
  8. ^ a b Albers, Kenda; Kragh, Katherine; Monnier, Adam; Pligge, Zachary; Stolze, Kellen; West, Josh; et al. (October 2010). "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2009 October thru 2010 April". The Minor Planet Bulletin. 37 (4): 152–158. Bibcode:2010MPBu...37..152A. ISSN 1052-8091. Retrieved 9 January 2018. 
  9. ^ a b "1227 Geranium (1931 TD)". Minor Planet Center. Retrieved 9 January 2018. 
  10. ^ a b Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1234) Elyna. Springer Berlin Heidelberg. pp. 102–103. ISBN 978-3-540-00238-3. Archived from the original on 12 March 2016. Retrieved 27 January 2018. 
  11. ^ Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1054) Forsytia. Springer Berlin Heidelberg. p. 90. ISBN 978-3-540-00238-3. Archived from the original on 24 September 2017. Retrieved 27 January 2018. 

External links[edit]