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7204 Ondřejov, provisional designation 1995 GH, is a stony asteroid from the middle region of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 3 April 1995, by Czech astronomer Petr Pravec at Ondřejov Observatory near Prague, Czech Republic.[8]

7204 Ondřejov
Discovery [1]
Discovered byP. Pravec
Discovery siteOndřejov Obs.
Discovery date3 April 1995
MPC designation(7204) Ondřejov
Named after
(town and observatory)[2]
1995 GH · 1980 WM3
main-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc36.42 yr (13,303 days)
Aphelion2.9941 AU
Perihelion2.3461 AU
2.6701 AU
4.36 yr (1,594 days)
0° 13m 33.24s / day
Physical characteristics
Dimensions5.685±0.163 km[4][5]
6.25 km (calculated)[3]
5.2334±0.0101 h[6]
0.10 (assumed)[3]
13.8[1] · 13.7[4] · 13.687±0.005 (R)[6] · 13.67±0.19[7] · 14.14[3]

This asteroid was the observatory's first numbered minor planet discovery.[2] It was named for the Czech village of Ondřejov and its discovering observatory.

Orbit and classificationEdit

Ondřejov orbits the Sun in the central main-belt at a distance of 2.3–3.0 AU once every 4 years and 4 months (1,594 days). Its orbit has an eccentricity of 0.12 and an inclination of 5° with respect to the ecliptic.[1] It was first identified as 1980 WM3 at Palomar Observatory in 1980, extending the body's observation arc by 15 years prior to its official discovery observation at Ondrejov.[8]

Physical characteristicsEdit

Rotation periodEdit

In December 2011, a rotational lightcurve of Ondřejov was obtained from photometric observations taken at the Palomar Transient Factory in California. It showed a rotation period of 5.2334 hours with a brightness variation of 0.55 magnitude (U=2).[6]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 5.9 kilometers in diameter and its surface has an albedo of 0.18,[4][5] while the Collaborative Asteroid Lightcurve Link assumes a lower albedo of 0.10 and calculates a diameter of 6.3 kilometers with an absolute magnitude of 14.14.[3]


This minor planet was named for both, the Czech village of Ondřejov, and its discovering Ondřejov Observatory, founded in 1898.[2]

Ondřejov is the Czech Republic's oldest astronomical observatory still in use. In 1953, the observatory was integrated into the Astronomical Institute and is now also owned by the Academy of Sciences of the Czech Republic. Ondřejov is located about 35 kilometers southeast of the country's capital, Prague.[2] The approved naming citation was published by the Minor Planet Center on 22 February 1997 (M.P.C. 29149).[9]


  1. ^ a b c d "JPL Small-Body Database Browser: 7204 Ondrejov (1995 GH)" (2017-05-02 last obs.). Jet Propulsion Laboratory. Retrieved 21 June 2017.
  2. ^ a b c d Schmadel, Lutz D. (2007). "(7204) Ondřejov". Dictionary of Minor Planet Names – (7204) Ondřejov. Springer Berlin Heidelberg. p. 583. doi:10.1007/978-3-540-29925-7_6350. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (7204) Ondrejov". Asteroid Lightcurve Database (LCDB). Retrieved 13 April 2016.
  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". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 17 May 2016.
  5. ^ a b c 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 5 December 2016.
  6. ^ 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:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 17 May 2016.
  7. ^ 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 17 May 2016.
  8. ^ a b "7204 Ondrejov (1995 GH)". Minor Planet Center. Retrieved 13 April 2016.
  9. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 May 2016.

External linksEdit