Discovery date 20 April 1950 Minor planet category main-belt · Phocaea Absolute magnitude 12.3 Discovery site Goethe Link Observatory Discoverer Indiana Asteroid Program | MPC designation 1575 Winifred Discovered 20 April 1950 Orbits Sun Asteroid group Asteroid belt | |
Discovered by Indiana University
(Indiana Asteroid Program) Named after Winifred Sawtelle
(staff member at USNO) Alternative names 1950 HH · 1928 HG
1939 GK · 1950 HD1
1977 UH1 | ||
1575 Winifred, provisional designation 1950 HH, is a stony Phocaea asteroid and slow rotator from the inner regions of the asteroid belt, approximately 9.5 kilometers in diameter. It was discovered on 20 April 1950, by astronomer R. C. Cameron of Indiana University during the Indiana Asteroid Program at Goethe Link Observatory in Indiana, United States.
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. Winifred was first identified as 1928 HG at Johannesburg Observatory in 1928, extending the body's observation arc by 22 years prior to its official discovery observation.
In July 2009, a rotational light-curve was obtained for this asteroid from photometric observations taken by American astronomer Brian D. Warner at his Palmer Divide Observatory in Colorado. It gave a well-defined rotation period of 7002125000000000000♠125±2 hours with an exceptionally high brightness amplitude of 7000120000000000000♠1.20 in magnitude (U=3), and no sign of a non-principal axis rotation (NPAR). The result supersedes a previous observation by French astronomer Laurent Bernasconi from May 2005, that gave a similar, yet less accurate period of 129 hours, and 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, Winifred 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 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 Sawtell Cameron. The naming was proposed by the discovering astronomer. Naming citation was published before November 1977 (M.P.C. 844).