_Picka.png) Modelled shape ofPicka from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | J. Palisa |
| Discovery site | Vienna Obs. |
| Discovery date | 21 March 1915 |
| Designations | |
| (803) Picka | |
Named after | Friedrich Pick (Czech physician)[2] |
| A915 FL · 1952 YH 1984 EC2 · A899 NE A915 FD · 1915 WS | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 104.50yr (38,169 d) |
| Aphelion | 3.4133AU |
| Perihelion | 2.9929 AU |
| 3.2031 AU | |
| Eccentricity | 0.0656 |
| 5.73 yr (2,094 d) | |
| 338.93° | |
| 0° 10m 18.84s / day | |
| Inclination | 8.6665° |
| 250.95° | |
| 58.556° | |
| Physical characteristics | |
| 5.0742±0.0006 h[10] | |
803 Picka (prov. designation:A915 FLor1915 WS) is a large and darkbackground asteroid from the outer regions of theasteroid belt. It was discovered on 21 March 1915, by Austrian astronomerJohann Palisa at theVienna Observatory.[1] The carbonaceousD-type asteroid has arotation period of 5.1 hours and measures approximately 57 kilometers (35 miles) in diameter. It was named after Czech physicianFriedrich Pick (1867–1921).[2]
Picka is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[4][5][6] It orbits the Sun in theouter asteroid belt at a distance of 3.0–3.4 AU once every 5 years and 9 months (2,094 days;semi-major axis of 3.2 AU). Its orbit has aneccentricity of 0.07 and aninclination of 9° with respect to theecliptic.[3] On 8 July 1899, the asteroid was first observed asA899 NE at theBoyden Station (800) of the Harvard Observatory in Arequipa, Peru. The body'sobservation arc begins with its official discovery observation byJohann Palisa atVienna Observatory on 21 March 1915.[1]
Thisminor planet was named after Czech physicianFriedrich Pick (1867–1921) from Prague, who was the first physician to introduce endoscopic methods in medicine. According to the 1917 edition of the astronomical calendar in German "Astronomischer Kalender für 1917", the asteroid was named by friends of the discoverer Johann Palisa. Thenaming was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 80).[2]
In theSDSS-based taxonomy,Picka is a darkD-type asteroid.[11] In the 1995 SMASS-I survey by Xu, it is classified as an uncommonT-type with some similarities to a D-type (TD).[5] The D-types asteroids are common in the outer main-belt and are very abundant among theJupiter trojan population.
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In April 2007, a rotationallightcurve ofPicka was obtained fromphotometric observations by French amateur astronomerPierre Antonini. Lightcurve analysis gave a well-definedrotation period of5.0742±0.0006 hours with a high brightness variation of0.47±0.01magnitude, indicative of an elongated shape (U=3).[10] Alternative and lower-rated photometric observations were made by Jean-Gabriel Bosch in February 2006, and again by Pierre Antonini in November 2010, which gave a period of5.13±0.05 and5.0752±0.0003 hours with an amplitude of0.43±0.03 and0.12±0.01 magnitude (U=2/3–).[10]
Lightcurve inversion also modeled the body's shape andpoles. In 2013, modelling by an international study using photometric data from theUS Naval Observatory, the Uppsala Asteroid Photometric Catalogue, thePalomar Transient Factory and theCatalina Sky Survey gave a concurring sidereal period of5.07478±0.00002 hours and twospin axes at (218.0°, 34.0°) and (53.0°, 41.0°) inecliptic coordinates (λ, β). The body's very elongated shape had already been indicated by the relatively high brightness variation measured during the direct photometric observations.[5][14]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Picka measures (46.50±2.2), (57.41±0.95) and (69.165±8.353) kilometers in diameter and its surface has analbedo of (0.1181±0.012), (0.079±0.003) and (0.035±0.102), respectively.[7][8][9] TheCollaborative Asteroid Lightcurve Link derives an albedo of0.1406 and a diameter of 46.72 kilometers based on anabsolute magnitude of 9.4.[13] On 13 May 2015, anasteroid occultation ofPicka gave a best-fit ellipse dimension of (57.0 km × 57.0 km), which is similar to that obtained by the Japanese Akari satellite. These timed observations are taken when the asteroid passes in front of a distant star. This observation still has received a low quality rating.[5]
