_Calvinia.png) Shape model ofCalvinia from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 26 May 1932 |
| Designations | |
| (1245) Calvinia | |
Named after | Calvinia[2] (South African city) |
| 1932 KF · 1948 VT 1950 CP · A906 FB A914 YB · A916 DC A917 KE | |
| main-belt[1][3] · (outer) background[4] · Koronis[4][5][6] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 112.59yr (41,125 d) |
| Aphelion | 3.1302AU |
| Perihelion | 2.6536 AU |
| 2.8919 AU | |
| Eccentricity | 0.0824 |
| 4.92 yr (1,796 d) | |
| 137.36° | |
| 0° 12m 1.44s / day | |
| Inclination | 2.8936° |
| 151.72° | |
| 208.24° | |
| Physical characteristics | |
| 26.84±3.5 km[7] 29.751±0.204 km[8][9] 30.444±0.137 km[10] 30.95±0.78 km[11] | |
| 4.8523±0.0001 h[12] | |
| 0.214[11] 0.2202[10] 0.221[8][9] 0.2713[7] | |
| Tholen =S[3][6] B–V = 0.847[4] U–B = 0.474[4] | |
| 9.89[7][8][10][11] 9.9[1][3][6] 10.11±0.03[13] | |
1245 Calvinia (prov. designation:1932 KF) is a stonyKoronian asteroid from the outer regions of theasteroid belt, approximately 30 kilometers (19 miles) in diameter. It was discovered on 26 May 1932, by South African astronomerCyril Jackson at theUnion Observatory in Johannesburg.[1] TheS-type asteroid is likely elongated and has arotation period of 4.9 hours.[6] It was named for the city ofCalvinia in South Africa.[2]
According toZappalà,Mothé-Diniz, as well asMilani andKnežević,Calvinia is a member of theKoronis family (605),[4][5] a very large outerasteroid family with nearly co-planar ecliptical orbits.[14] Interestingly, in one of the most recent and complete syntheticHCM-analysis byNesvorný,Calvinia is not a Koronian asteroid but belongs to thebackground population.[4]
It orbits the Sun in theouter main-belt at a distance of 2.7–3.1 AU once every 4 years and 11 months (1,796 days;semi-major axis of 2.89 AU). Its orbit has aneccentricity of 0.08 and aninclination of 3° with respect to theecliptic.[3] The asteroid was first observed asA906 FB at theHeidelberg Observatory in March 1906. The body'sobservation arc begins with its official discovery observation at Johannesburg in May 1932.[1]
Thisminor planet was named after the regional cityCalvinia in the Cape Province of South Africa.[2] The officialnaming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 115).[2]
In theTholen classification,Calvinia is a common stonyS-type asteroid,[4] which is also the overallspectral type for members of the Koronis family.[14]: 23 In the Barucci taxonomy (1987), it is an S0-type asteroid.[4]
In October 2017, a rotationallightcurve ofCalvinia was obtained fromphotometric observations by Romain Montaigut, Christophe Gillier and Arnaud Leroy. Lightcurve analysis gave arotation period of4.8523±0.0001 hours with a brightness variation of 0.28magnitude (U=3).[12]
Other rotational were obtained by (ordered by increasing period determinations ) Brines (4.73 h; Δ0.35 mag; U=3-) in 2016,[15] byLagerkvist (4.8 h; Δ0.52 mag; U=2) and (4.85 h; Δ0.7 mag; U=2) in 1975 and 1978,[16][17] respectively, byErikson (4.84 h; U=3) in 1990,[18] by Slivan (4.8512 h; Δ0.37 mag; U=3) in 2002, byRoy (4.85129 h; Δ0.50 mag; U=3-),[12] and byTedesco (4.855 h; Δ0.63 mag; U=3) in 1979.[6]
A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave a concurring period of4.85148±0.00001 hours, as well as twospin axes at (52.0°, −51.0°) and (235.0°, −43.0°) inecliptic coordinates (λ, β).[19]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Calvinia measures between 26.84 and 30.95 kilometers in diameter and its surface has analbedo between 0.214 and 0.2713.[7][8][9][10][11] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.2689 and a diameter of 26.83 kilometers based on anabsolute magnitude of 9.9.[6]
