1233 Kobresia

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
1233 Kobresia
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date10 October 1931
MPC designation(1233) Kobresia
Named after
Kobresia (flowering plant)[2]
1931 TG2 · 1927 TB
1951 QJ · 1951 RP1
1954 EG
main-belt · (inner)[3]
background [4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc90.15 yr (32,928 days)
Aphelion2.6976 AU
Perihelion2.4143 AU
2.5560 AU
4.09 yr (1,493 days)
0° 14m 28.32s / day
Physical characteristics
Dimensions29.73±7.16 km[5]
30.239±10.28 km[6]
31.46±15.67 km[7]
33.323±0.159 km[8]
33.45 km (derived)[3]
33.50±0.8 km[9]
36.06±0.60 km[10]
36.167±0.249 km[11]
27.76±0.05 h[12]
27.83±0.01 h[12]
0.0396 (derived)[3]
C[14] · S (assumed)[3]
11.30[9][10][11] · 11.50[1][3][5][8] · 11.57[7] · 11.91[6] · 11.91±1.30[14]

1233 Kobresia, provisional designation 1931 TG2, is a carbonaceous background asteroid from the central regions of the asteroid belt, approximately 33 kilometers in diameter. It was discovered on 10 October 1931, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany.[15] The asteroid was named for the grass-like flowering plant Kobresia, a genus in the sedge family.[2]

Orbit and classification[edit]

Kobresia is a non-family asteroid from the main belt's background population.[4] It orbits the Sun in the central main-belt at a distance of 2.4–2.7 AU once every 4 years and 1 month (1,493 days; semi-major axis of 2.56 AU). Its orbit has an eccentricity of 0.06 and an inclination of 6° with respect to the ecliptic.[1]

The body's observation arc begins with its first observation as 1927 TB at Heidelberg in October 1927, or four years prior to its official discovery observation.[15]

Physical characteristics[edit]

Kobresia has been characterized as a carbonaceous C-type asteroid by Pan-STARRS photometric survey.[14]

Rotation period[edit]

Two rotational lightcurves of Kobresia were obtained by French amateur astronomer Pierre Antonini. Lightcurve analysis of his photometric observations made in 2004 and 2006, gave a rotation period of 27.76 and 27.83 hours with a brightness amplitude of 0.32 and 0.34 magnitude, respectively (U=2/2).[12] While not being a slow rotator, Kobresia's period is longer than that of the average asteroid.

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, Kobresia measures between 29.73 and 36.167 kilometers in diameter and its surface has an albedo between 0.0305 and 0.0475.[5][6][7][8][9][10][11][13]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0396 and a diameter of 33.45 kilometers based on an absolute magnitude of 11.5.[3]


This minor planet was named after a genus in the Cyperaceae family, Kobresia, a grass-like flowering plant, commonly known as "bog sedges". The author of the Dictionary of Minor Planet Names contacted Dutch astronomer Ingrid van Houten-Groeneveld in order to confirm the meaning of this asteroid's name.[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.[16] 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).[16]

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).[17]


  1. ^ a b c d "JPL Small-Body Database Browser: 1233 Kobresia (1931 TG2)" (2017-11-27 last obs.). Jet Propulsion Laboratory. Retrieved 9 January 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1233) Kobresia". Dictionary of Minor Planet Names – (1233) Kobresia. Springer Berlin Heidelberg. p. 102. doi:10.1007/978-3-540-29925-7_1234. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1233) Kobresia". 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 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 9 January 2018.
  6. ^ a b c d Masiero, Joseph R.; Nugent, C.; Mainzer, A. K.; Wright, E. L.; Bauer, J. M.; Cutri, R. M.; et al. (October 2017). "NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos". The Astronomical Journal. 154 (4): 10. arXiv:1708.09504. Bibcode:2017AJ....154..168M. doi:10.3847/1538-3881/aa89ec.
  7. ^ 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 9 January 2018.
  8. ^ 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 9 January 2018.
  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: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Archived from the original on 2016-06-03. Retrieved 9 January 2018.
  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 9 January 2018.
  11. ^ 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". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
  12. ^ a b c Behrend, Raoul. "Asteroids and comets rotation curves – (1233) Kobresia". Geneva Observatory. Retrieved 9 January 2018.
  13. ^ 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:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
  14. ^ a b c 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 9 January 2018.
  15. ^ a b "1233 Kobresia (1931 TG2)". Minor Planet Center. Retrieved 9 January 2018.
  16. ^ a b Schmadel, Lutz D. (2007). "(1234) Elyna". Dictionary of Minor Planet Names – (1234) Elyna. Springer Berlin Heidelberg. pp. 102–103. doi:10.1007/978-3-540-29925-7_1235. ISBN 978-3-540-00238-3.
  17. ^ Schmadel, Lutz D. (2007). "(1054) Forsytia". Dictionary of Minor Planet Names – (1054) Forsytia. Springer Berlin Heidelberg. p. 90. doi:10.1007/978-3-540-29925-7_1055. ISBN 978-3-540-00238-3.

External links[edit]