_N%25C3%25A4si.png) Shape model of Näsi derived from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Observatory |
| Discovery date | 20 January 1939 |
| Designations | |
| (1534) Näsi | |
Named after | Näsijärvi(Finnish lake)[2] |
| 1939 BK · 1933 UQ 1957 EA · 1960 UB 1962 JA · A915 VB A924 WE · A924 YE | |
| main-belt · (middle) Chloris | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 91.56 yr (33,443 days) |
| Aphelion | 3.4155AU |
| Perihelion | 2.0404 AU |
| 2.7279 AU | |
| Eccentricity | 0.2520 |
| 4.51yr (1,646 days) | |
| 174.04° | |
| 0° 13m 7.68s / day | |
| Inclination | 9.7942° |
| 62.135° | |
| 42.826° | |
| Physical characteristics | |
| Dimensions | 18.32±5.21 km[3] 19.51±0.36 km[4] 19.92±0.65 km[5] 22.11 km(derived)[6] 22.12±0.9 km(IRAS:6)[7] 27.52±6.50 km[8] |
| 5.98±0.02 h[9] 7.93161±0.00005 h[10] 7.9338±0.0003 h[11] 7.94±0.02 h[12] 9.75h[13] | |
| 0.035±0.015[8] 0.07±0.01[5] 0.0721(derived)[6] 0.0754±0.006(IRAS:6)[7] 0.08±0.04[3] 0.100±0.004[4] | |
| SMASS = Cgh[1] · C[6][14] | |
| 11.7[7][4] · 11.75[6][13] · 11.80[3] · 11.88±0.24[14] · 11.9[1] · 11.93[5] · 11.96[11] · 12.05[8] | |
1534 Näsi (provisional designation1939 BK) is a carbonaceousasteroid from the middle region of theasteroid belt, approximately 20 kilometers in diameter.
It was discovered on 20 January 1939, by Finnish astronomerYrjö Väisälä atTurku Observatory in Southwest Finland, and later named for the Finnish lakeNäsijärvi.[2][15]
Näsi orbits the Sun in thecentral main-belt at a distance of 2.0–3.4 AU once every 4 years and 6 months (1,646 days). Its orbit has aneccentricity of 0.25 and aninclination of 10° with respect to theecliptic.[1] It was first identified asA915 VB atSimeiz Observatory in 1915. The body'sobservation arc begins 15 years prior to its official discovery with its identification as1924 YE atHeidelberg Observatory.[15]
In April 2007, the so-far best rated rotationallightcurve of Näsi was obtained by Jason Sauppe atOakley Observatory in the United States. The lightcurve analysis gave arotation period of 7.94 hours with a brightness variation of 0.35magnitude (U=3-).[12]
Periods from other photometric observations were obtained by astronomersRené Roy in May 2016 (5.98 hours, Δ0.47 mag,U=2+),[9]Giovanni de Sanctis in the 1990s (9.75 hours, Δ0.22 mag,U=2),[13]Adrián Galád in October 2005 (7.9338 hours, Δ0.51 mag,U=2-),[11] and a period of 7.93161 hours modeled from various data sources and published in 2016 (U=n.a.).[10]
In theSMASS taxonomy, the carbonaceousC-type asteroid is also classified as a Cgh-subtype. According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission, Näsi measures between 18.32 and 27.52 kilometers in diameter and its surface has analbedo between 0.035 and 0.100.[3][4][5][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0721 and a diameter of 22.11 kilometers based on anabsolute magnitude of 11.75.[6]
Thisminor planet is named for the large Finnish lakeNäsijärvi, sometimes called "Näsi". It measures 256 square kilometers (99 sq mi) in size and is located only 95 metres above sea level.[2] The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3929).[16]
