| Discovery[1] | |
|---|---|
| Discovered by | T. Urata |
| Discovery site | Nihondaira Obs. |
| Discovery date | 20 January 1993 |
| Designations | |
| (7776) Takeishi | |
Named after | Masanori Takeishi[1] (Japanese astronomer) |
| 1993 BF · 1981 RJ 1995 UM4 | |
| main-belt[1][2] · (inner)[3] background[4] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 35.66yr (13,023 d) |
| Aphelion | 2.6137AU |
| Perihelion | 1.9042 AU |
| 2.2590 AU | |
| Eccentricity | 0.1571 |
| 3.40 yr (1,240 d) | |
| 258.36° | |
| 0° 17m 25.08s / day | |
| Inclination | 9.4908° |
| 309.46° | |
| 39.968° | |
| Physical characteristics | |
| 5.99±1.19 km[5] 6.165±0.135 km[6][7] 7.46 km (calculated)[3] | |
| 8.65±0.03 h[8] 8.90 h[a] | |
| 0.20 (assumed)[3] 0.29±0.13[5] 0.353±0.051[6][7] | |
| S (assumed)[3] | |
| 12.8[7] 13.0[2][3] 13.18±0.27[9] 13.34[5] | |
7776 Takeishi, provisional designation1993 BF, is a backgroundasteroid from the inner regions of theasteroid belt, approximately 6 kilometers (4 miles) in diameter. It was discovered on 20 January 1993, by Japanese astronomerTakeshi Urata at theNihondaira Observatory in Japan.[1] The assumedS-type asteroid has arotation period of 8.9 hours.[3] It was named after Japanese amateur astronomerMasanori Takeishi.[1]
Takeishi is a non-family asteroid from the main belt'sbackground population.[4] It orbits the Sun in theinner asteroid belt at a distance of 1.9–2.6 AU once every 3 years and 5 months (1,240 days;semi-major axis of 2.26 AU). Its orbit has aneccentricity of 0.16 and aninclination of 9° with respect to theecliptic.[2] The body'sobservation arc begins with first observations as1981 RJ atAnderson Mesa Station in September 1981, more than 11 years prior to its official discovery observation.[1]
Takeishi is an assumed, stonyS-type asteroid.[3]
Two rotationallightcurves ofTakeishi have been obtained fromphotometric observations by French amateur astronomerPierre Antonini andLaurent Bernasconi, as well as by American William Koff at the Antelope Hills Observatory (H09) in Colorado. The fragmentary lightcurves gave a poorly determinedrotation period of 8.65 and 8.90 hours, respectively. Both showed a minuscule brightness amplitude of 0.05magnitude (U=1/1).[3][8][a]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Takeishi measures between 5.99 and 6.165 kilometers in diameter and its surface has analbedo between 0.29 and 0.353,[5][6][7] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20, and calculates a diameter of 7.46 kilometers based on anabsolute magnitude of 13.0.[3]
Thisminor planet was named after Japanese amateur astronomer anddiscoverer of minor planets,Masanori Takeishi (born 1950). Between 1975 and 1993, he was a chief editor of theJapan Astronomical Circular.[1] The official naming citation was published by theMinor Planet Center on 14 December 1997 (M.P.C. 31027).[10]
