725 Amanda

725 Amanda ("prov. designation:" "or" ) is a dark background asteroid, approximately in diameter, that is located in the central regions of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 21 October 1911. The carbonaceous C-type asteroid (CSU/C0) has a short rotation period of 3.7 hours. It was named after Amanda Schorr, wife of German astronomer Richard Schorr (1867–1951).
Orbit and classification.
"Amanda" is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the central asteroid belt at a distance of 2.0–3.1 AU once every 4 years and 2 months (1,507 days; semi-major axis of 2.57 AU). Its orbit has an eccentricity of 0.22 and an inclination of 4° with respect to the ecliptic. The body's observation arc begins at Vienna Observatory on 29 September 1915, almost four years after its official discovery observation.
Naming.
This minor planet was named after Amanda Schorr, wife of Richard Schorr (1867–1951), a German astronomer at Bergedorf Observatory, after whom asteroid 1235 Schorria and lunar crater "Schorr" were named. The asteroid's name was proposed by Palisa in 1913, on the occasion of the 24th meeting of the "Astronomische Gesellschaft" in Hamburg, Germany (). The was also mentioned in "The Names of the Minor Planets" by Paul Herget in 1955 ().
Physical characteristics.
In the Tholen classification, "Amanda"s spectral type is closest to that of a carbonaceous C-type asteroid, yet also somewhat similar to a stony S-type with an "unusual" spectrum (CSU). In the taxonomy by Barucci (1987), the asteroid is a dark C-type (C0).
Rotation period and poles.
A rotational lightcurve of "Amanda" was obtained from photometric observations by European astronomers at the La Silla Observatory before 1995. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of magnitude ().
In October 2010, French amateur astronomer Maurice Audejean determined a concurring period of () hours with an amplitude of () magnitude (), while in August 2018, a further observation by the TESS-team reported a period of () hours and an amplitude of () magnitude ().
In 2016, a modeled lightcurve gave a sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (145.0°, −63.0°) and (320.0°, −70.0°) in ecliptic coordinates (λ, β).
Diameter and albedo.
According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), "Amanda" measures (), () and () in diameter and its surface has an albedo of (), () and (), respectively.
The "Collaborative Asteroid Lightcurve Link" derives an albedo of 0.0824 and calculates a diameter of 21.56 kilometers based on an absolute magnitude of 11.66. Alternative mean-diameters published by the WISE team include (), (), () and () with a corresponding albedo of (), (), () and ().