7204 Ondřejov

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 by	P. Pravec
Discovery site	Ondřejov Obs.
Discovery date	3 April 1995
Designations
MPC designation	(7204) Ondřejov
Named after	Ondřejov (town and observatory)[2]
Alternative designations	1995 GH · 1980 WM3
Minor planet category	main-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	36.42 yr (13,303 days)
Aphelion	2.9941 AU
Perihelion	2.3461 AU
Semi-major axis	2.6701 AU
Eccentricity	0.1213
Orbital period (sidereal)	4.36 yr (1,594 days)
Mean anomaly	168.03°
Mean motion	0° 13m 33.24s / day
Inclination	4.8597°
Longitude of ascending node	172.33°
Argument of perihelion	235.90°
Physical characteristics
Dimensions	5.685±0.163 km[4][5] 6.25 km (calculated)[3]
Synodic rotation period	5.2334±0.0101 h[6]
Geometric albedo	0.10 (assumed)[3] 0.181±0.009[4][5]
Spectral type	S[3]
Absolute magnitude (H)	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 classification

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 characteristics

Rotation period

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 albedo

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]

Naming

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]