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.
The stony S-type asteroid is a member of the Phocaea family (701), a group of asteroids with similar orbital characteristics, named after the family's namesake 25 Phocaea.[4] 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.[1]
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.[12]
Physical characteristics
Rotational lightcurve
In July 2009, a rotational lightcurve 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 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).[9] 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).[10]
Diameter and albedo
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,[5][6][7][8] while the Collaborative Asteroid Lightcurve Link derives a higher albedo of 0.31 and a diameter of 9.5 kilometers with an absolute magnitude of 12.0.[3]
^Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN978-3-642-01964-7.