_Bessel.png) Shape model of Bessel from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Observatory |
| Discovery date | 24 February 1938 |
| Designations | |
| (1552) Bessel | |
Named after | Friedrich Bessel (German astronomer)[2] |
| 1938 DE1 · 1933 FJ1 1948 EH · 1951 UF | |
| main-belt · Eos[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 84.11 yr (30,722 days) |
| Aphelion | 3.3068AU |
| Perihelion | 2.7174 AU |
| 3.0121 AU | |
| Eccentricity | 0.0978 |
| 5.23yr (1,909 days) | |
| 185.26° | |
| 0° 11m 18.6s / day | |
| Inclination | 9.8367° |
| 9.9835° | |
| 39.607° | |
| Physical characteristics | |
| Dimensions | 16.63±0.84 km[4] 18.33 km(derived)[3] 18.514±0.066 km[5] 18.817±0.101 km[6] |
| 8.96318±0.00002 h[a] 8.996±0.006h[7] | |
| 0.1448(derived)[3] 0.1514±0.0332[6] 0.156±0.023[5] 0.193±0.024[4] | |
| S[3] | |
| 11.3[4][6] · 11.4[1][3] · 11.53±0.24[8] | |
1552 Bessel (provisional designation1938 DE1) is a stony Eoanasteroid from the outer regions of theasteroid belt, approximately 18 kilometers in diameter. It was discovered on 24 February 1938, by Finnish astronomerYrjö Väisälä atTurku Observatory in Southwest Finland, and named after German astronomerFriedrich Bessel.[2][9]
Bessel is astony asteroid and a member of theEos family that orbits the Sun in theouter main-belt at a distance of 2.7–3.3 AU once every 5 years and 3 months (1,909 days). Its orbit has aneccentricity of 0.10 and aninclination of 10° with respect to theecliptic.[1] First observed as1933 FJ1 atHeidelberg in 1933, the body'sobservation arc begins at Turku, 5 days prior to its official discovery observation.[9]
Thisminor planet was named after German astronomerFriedrich Wilhelm Bessel (1789–1846), who measured the firststellar parallax in 1838. His measured parallax of 0.314 arcseconds for61 Cygni gave a distance of 10.3 light-years, which is 9.6% off today's measured distance of 11.4 light-years. Bessel is also honored by the lunar craterBessel.[2][10] The officialnaming citation was published by theMinor Planet Center on 30 January 1964 (M.P.C. 2278).[11]
In March 2011, a rotationallightcurve of Bessel was obtained from photometric observations by Italian amateur astronomerSilvano Casulli. Lightcurve analysis gave a well-definedrotation period of 8.996 hours with a brightness variation of 0.29magnitude (U=3).[7]
In 2016, a modeled lightcurve using photometric data from various sources gave a concurring period of 8.96318 hours, as well as aspin axis of (61.0°, −50.0°) inecliptic coordinates (λ, β).[a]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission, Bessel measures between 16.63 and 18.817 kilometers in diameter, and its surface has analbedo between 0.1514 and 0.193.[4][5][6] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.1448 and a diameter of 18.33 kilometers with anabsolute magnitude of 11.4.[3]
