| Discovery[1] | |
|---|---|
| Discovered by | L. Kohoutek |
| Discovery site | Bergedorf Obs. |
| Discovery date | 26 October 1971 |
| Designations | |
| (1995) Hajek | |
Named after | Tadeáš Hájek(astronomer)[2] |
| 1971 UP1 · 1941 EA | |
| main-belt · (middle)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 76.21 yr (27,836 days) |
| Aphelion | 2.6677AU |
| Perihelion | 2.3911 AU |
| 2.5294 AU | |
| Eccentricity | 0.0547 |
| 4.02yr (1,469 days) | |
| 6.1573° | |
| 0° 14m 42s / day | |
| Inclination | 10.825° |
| 47.232° | |
| 134.65° | |
| Physical characteristics | |
| Dimensions | 6.50 km(calculated)[3] 12.683±0.288 km[4][5] 14.45±2.58 km[6] 15.29±1.04 km[7] |
| 10h[8] | |
| 0.040±0.025[6][5] 0.063±0.010[7] 0.0833±0.0249[4] 0.20(assumed)[3] | |
| P[4] · X[3][9][10] | |
| 12.80[4][7] · 13.06±0.33[9] · 13.3[1][3][6] | |
1995 Hajek, provisional designation1971 UP1, is a metallicasteroid from the middle region of theasteroid belt, approximately 13 kilometers in diameter.
It was discovered on 26 October 1971, by Czech astronomerLuboš Kohoutek at theBergedorf Observatory in Hamburg, Germany.[11] It was named after Renaissance astronomerTadeáš Hájek.[2]
Hajek orbits the Sun in themiddle main-belt at a distance of 2.4–2.7 AU once every 4.02 years (1,469 days). Its orbit has aneccentricity of 0.05 and aninclination of 11° with respect to theecliptic.[1] It was first identified as1941 EA at Heidelberg in 1941. The body's used observation was aprecovery taken atPalomar Observatory in 1951, extending itsobservation arc by 20 years prior to the official discovery observation at Heidelberg.
A first rotationallightcurve ofHajek was obtained by French amateur astronomers Alain Klotz, Marc Rieugné, and Pierre Thierry in October 2013. It gave a provisionalrotation period of 10 hours with a brightness variation of 0.10magnitude (U=1+).[8]
Hajek has thespectral properties of a metallicX-type asteroid.[3][9][10] It is also classified as a darkP-type asteroid by NASA'sWide-field Infrared Survey Explorer (WISE).[4]
According to the surveys carried out by the JapaneseAkari satellite and WISE space-telescope with its subsequentNEOWISE mission,Hajek measures between 12.7 and 15.3 kilometers in diameter and its surface has analbedo of 0.040 and 0.083.[4][6][7] TheCollaborative Asteroid Lightcurve Link strongly disagrees with the space-based observations and assumes a standard albedo for stony asteroids of 0.200 and calculates a much smaller diameter of 6.5 kilometers.[3] These contrasting albedo and diameter figures closely correspond to a generic magnitude-to-diameter conversion, where, for an absolute magnitude of 13.3, the body's diameter is in the range of 6 to 14 kilometers, based on an albedo between 0.05 and 0.25.[12]
Thisminor planet was named after the Bohemian astronomerTadeáš Hájek (1525–1600), better known by his Latinized name, Thaddaeus Hagecius. He was one of the founders of modern stellar and cometary astronomy, who studied theGreat Comet of 1577 and the supernovaSN 1572, also known asTycho's Nova. The lunar craterHagecius is also named in his honour.[2] The officialnaming citation was published by theMinor Planet Center on 1 April 1978 (M.P.C. 4358).[13]
