_Kemi.png) Shape model of Kemi from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | H. Alikoski |
| Discovery site | Turku Obs. |
| Discovery date | 21 October 1938 |
| Designations | |
| (1508) Kemi | |
Named after | Kemi andKemi River[2] (Finnish town andriver) |
| 1938 UP · 1935 FA 1938 UO | |
| Mars-crosser[1][3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 81.79 yr (29,873 days) |
| Aphelion | 3.9264AU |
| Perihelion | 1.6167 AU |
| 2.7716 AU | |
| Eccentricity | 0.4167 |
| 4.61yr (1,685 days) | |
| 354.04° | |
| 0° 12m 48.96s / day | |
| Inclination | 28.723° |
| 14.298° | |
| 92.892° | |
| Mars MOID | 0.3966 AU |
| Physical characteristics | |
| Dimensions | 15.78±1.58 km[5] 15.9±1.6 km[6] 16±2 km[7] 17.98±1.34 km[8] 21.86 km(calculated)[4] |
| 9.15h[9] 9.19±0.05 h[10] 9.19182±0.00005 h[11] 9.196±0.001 h[12][a] 11.36 h[13] | |
| 0.057(assumed)[4] 0.084±0.013[8] 0.109±0.022[5] 0.11±0.02[6][7] | |
| Tholen = BCF[1] SMASS =C[1][4] B–V = 0.645[1] U–B = 0.249[1] | |
| 12.03[1][4][5][6][7][8] | |
1508 Kemi (provisional designation1938 UP) is an eccentric, carbonaceousasteroid and one of the largestMars-crossers, approximately 17 kilometers in diameter. Discovered byHeikki Alikoski atTurku Observatory in 1938,[3] the asteroid was later named after the Finnish town ofKemi and theKemi River.[2]
Kemi was discovered on 21 October 1938, by Finnish astronomerHeikki Alikoski at theIso-Heikkilä Observatory in Turku, Finland.[3] It was independently discovered by Hungarian astronomerGyörgy Kulin atKonkoly Observatory near Budapest on 30 October 1938.[2] TheMinor Planet Center, however, only acknowledges the first discoverer.[3] The asteroid was first identified as1935 FA atUccle Observatory in March 1935.[3]
Kemi is aMars-crossing asteroid as it crosses the orbit ofMars at 1.666 AU. Because of its high inclination, it has been grouped with thePallas family (801), anasteroid family of bright carbonaceous asteroids, as well as with the "Phaethon group", despite its untypical spectrum.[14][15]
It orbits the Sun at a distance of 1.6–3.9 AU once every 4 years and 7 months (1,685 days). Its orbit has aneccentricity of 0.42 and aninclination of 29° with respect to theecliptic.[1] The body'sobservation arc begins at Uccle in May 1935, more than 3 years prior to its official discovery observation at Turku.[3]
In theSMASS classification, Kemi is a common carbonaceousC-type asteroid.[1] In theTholen classification, the body'sspectral type is ambiguous (BCF), closest to that of a bright carbonaceousB-type and somewhat similar to a C- andF-type asteroid.[1]
Several rotationallightcurves of Kemi have been obtained from photometric observations since the 1990s. Analysis of the lightcurves gave a consolidatedrotation period of 9.196 hours with a brightness variation between of 0.25 and 0.55magnitude (U=2/3/3/2).[9][10][12][13][a]
In 2016, an international study modeled a lightcurve with a concurring period of 9.19182 hours. It also determined two spin axis at (352.0°, 72.0°) and (166.0°, 73.0°) inecliptic coordinates (λ, β).[11]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Kemi measures between 15.78 and 17.98 kilometers in diameter and its surface has analbedo between 0.084 and 0.11.[5][6][7][8] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 21.86 kilometers based on anabsolute magnitude of 12.03.[4]
Thisminor planet was named after the Finnish town ofKemi and theKemi River (Kemijoki), the largest river in Finland, on which the town lies. The naming agrees with the established pattern of giving high-inclination asteroids four-letter names.[2] The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3928).[16]
