_Saimaa.png) Shape model of Saimaa derived from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Obs. |
| Discovery date | 19 January 1939 |
| Designations | |
| (1533) Saimaa | |
Named after | Saimaa(Finnish lake)[2] |
| 1939 BD · 1934 FA 1936 QC · 1936 RP | |
| main-belt · (outer) Eos[3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 80.71 yr (29,480 days) |
| Aphelion | 3.1226AU |
| Perihelion | 2.8990 AU |
| 3.0108 AU | |
| Eccentricity | 0.0371 |
| 5.22yr (1,908 days) | |
| 346.96° | |
| 0° 11m 19.32s / day | |
| Inclination | 10.710° |
| 156.74° | |
| 10.478° | |
| Physical characteristics | |
| Dimensions | 24.298±0.279 km[5] 26.13±1.5 km[6] 26.16 km(derived)[3] 27.88±1.68 km[7] |
| 7.08h[8] 7.1181±0.0002 h[9] | |
| 0.107±0.014[7] 0.1216±0.016[6] 0.1270(derived)[3] 0.141±0.025[5] 0.165±0.034[5] | |
| Tholen =S[1][3] B–V = 0.790[1] U–B = 0.450[1] | |
| 10.77[3][8] · 10.77±0.26[10] · 10.82[1][5][6][7] | |
1533 Saimaa (provisional designation1939 BD) is a stonyEos asteroid from the outer regions of theasteroid belt, approximately 26 kilometers in diameter. It was discovered on 19 January 1939, by astronomerYrjö Väisälä at theIso-Heikkilä Observatory near Turku, Finland.[11] The asteroid was named after lakeSaimaa in Finland.[2]
Saimaa is a member theEos family (606),[4] the largestasteroid family of theouter main belt consisting of nearly 10,000 asteroids.[12]: 23 It orbits the Sun at a distance of 2.9–3.1 AU once every 5 years and 3 months (1,908 days). Its orbit has aneccentricity of 0.04 and aninclination of 11° with respect to theecliptic.[1] The asteroid was first identified as1934 FA atUccle Observatory in March 1934. The body'sobservation arc begins with its identification as1936 QC atHeidelberg Observatory in August 1936, more than 2 years prior to its official discovery observation at Turku.[11]
In theTholen classification, Saimaa is a common stonyS-type asteroid.[1][3] The overallspectral type for members of the Eos family is that of aK-type.[12]: 23
In September 1983, a first rotationallightcurve of Saimaa was obtained from photometric observations by American astronomerRichard Binzel atCTIO andMcDonald Observatory. Lightcurve analysis gave a well-definedrotation period of 7.08 hours with a brightness variation of 0.18magnitude (U=3).[8] In February 2007, another lightcurve obtained by French amateur astronomerRené Roy gave a concurring period of 7.1181 hours and an amplitude of 0.26 magnitude (U=3).[9]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, Saimaa measures between 22.40 and 27.88 kilometers in diameter and its surface has analbedo between 0.107 and 0.165.[5][6][7]
TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.1270 and a diameter of 26.16 kilometers based on anabsolute magnitude of 10.77.[3]
Thisminor planet was named after lakeSaimaa in southeastern Finland. With an overall area of 4,400 square kilometres (1,700 sq mi), it is the country'slargest lake and one of thelargest lakes in Europe.[2] The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3929).[13]
