1575 Winifred

1575 Winifred

Discovery
Discovered by	R. C. Cameron (Indiana University)
Discovery site	Goethe Link Obs.
Discovery date	20 April 1950
Designations
MPC designation	1575 Winifred
Named after	Winifred Sawtelle (staff member at USNO)
Alternative names	1950 HH · 1928 HG 1939 GK · 1950 HD1 1977 UH1
Minor planet category	main-belt · Phocaea
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	87.84 yr (32,083 days)
Aphelion	2.7996 AU
Perihelion	1.9488 AU
Semi-major axis	2.3742 AU
Eccentricity	0.1791
Orbital period	3.66 yr (1,336 days)
Mean anomaly	356.93°
Inclination	24.825°
Longitude of ascending node	206.84°
Argument of perihelion	348.33°
Physical characteristics
Dimensions	9.3 km 9.31±1.0 km (IRAS) 9.441±0.131 km 10.66±0.43 km 9.45 km (derived)
Rotation period	125±2 h 129 h
Geometric albedo	0.2452±0.064 0.2388±0.0311 0.247±0.034 0.3134 (derived)
Spectral type	S
Absolute magnitude (H)	12.0 12.3 11.36±1.19

1575 Winifred, provisional designation 1950 HH, is a stony Phocaea asteroid and slow rotator from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 20 April 1950, by astronomer R. C. Cameron of Indiana University at the U.S. Goethe Link Observatory, Indiana.

The stony S-type asteroid is a member of the Phocaea family, a group of asteroids with similar orbital characteristics, named after the family's namesake 25 Phocaea. It orbits the Sun at a distance of 1.9–2.8 AU once every 3 years and 8 months (1,336 days). Its orbit has an eccentricity of 0.18 and an inclination of 25° with respect to the ecliptic. The first precovery was taken at Johannesburg Observatory in 1928, extending the asteroid's observation arc by 22 years prior to its discovery.

In July 2009, a rotational light-curve was obtained for this asteroid from photometric observations made by American astronomer Brian Warner at the U.S. Palmer Divide Observatory in Colorado. The well-defined light-curve rendered a long rotation period of 125±2 hours with an exceptionally high brightness amplitude of 1.20 in magnitude (U=3), and no sign of a non-principal axis rotation (NPAR). The result superseded a previous observation by French astronomer Laurent Bernasconi in May 2005, that gave a similar, yet less accurate period of 129 hours, with a smaller amplitude of 0.51 in magnitude (U=1).

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid has an albedo of 0.24 to 0.25 and a diameter between 9.3 and 10.7 kilometers, while the Collaborative Asteroid Lightcurve Link derives a much higher albedo of 0.31 and a diameter of 9.5 kilometers.

The minor planet was named for a staff member of the United States Naval Observatory in Washington D.C., Miss Winifred Sawtelle. The naming was proposed by the discovering astronomer. Naming citation was published before November 1977 (M.P.C. 844).

See also

• Indiana Asteroid Program

External links

• Asteroid Lightcurve Database (LCDB), query form (info)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1575 Winifred at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters