| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 10 October 1931 |
| Designations | |
| (1272) Gefion | |
| Pronunciation | /ˈɡeɪfiɒn/ or/ˈɡɛfiɒn/[2] |
Named after | Gefjon[3] (Norse mythology) |
| 1931 TZ1 · A917 SF | |
| main-belt · (middle) Gefion[4] | |
| Adjectives | Gefionian/ɡɛfiˈoʊniən/[5] |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 99.50 yr (36,344 days) |
| Aphelion | 3.2076AU |
| Perihelion | 2.3604 AU |
| 2.7840 AU | |
| Eccentricity | 0.1521 |
| 4.65yr (1,697 days) | |
| 215.36° | |
| 0° 12m 43.92s / day | |
| Inclination | 8.4185° |
| 321.56° | |
| 3.6671° | |
| Physical characteristics | |
| Dimensions | 6.965±0.169 km[6] 7.016±0.066 km[7] 12.62 km(calculated)[8] |
| 2.900±0.0012h[9] 3.087±0.0005h[9] | |
| 0.057(assumed)[8] 0.2489±0.0256[7] 0.252±0.041[6] | |
| SMASS =Sl[1] C(assumed)[8] | |
| 12.785±0.005(R)[9] · 12.9[7] · 13.0[1] · 13.01±0.21[10] · 13.22[8] | |
1272 Gefion, provisional designation1931 TZ1, is a stonyasteroid andparent body of theGefion family from the central region of theasteroid belt, approximately 7 kilometers in diameter. It was discovered on 10 October 1931, by astronomerKarl Reinmuth at theHeidelberg Observatory in Germany. The asteroid was named afterGefjon from Norse mythology.[3]
Gefion is the namesake andparent body of theGefion family (516),[4] a largefamily of stony asteroids in the intermediate main belt.[11]: 23 The family is also a suspected source of theL chondrites, common group ofmeteorites.[12]
It orbits the Sun in thecentral main-belt at a distance of 2.4–3.2 AU once every 4 years and 8 months (1,697 days;semi-major axis of 2.78 AU). Its orbit has aneccentricity of 0.15 and aninclination of 8° with respect to theecliptic.[1]
The asteroid was first identified asA917 SF at Heidelberg in September 1917. The body'sobservation arc begins at Heidelberg, six days after its official discovery observation.[13]
In theSMASS classification,Gefion is a Sl-subtype that transitions from the common stonyS-type asteroids to the rather rareL-types.[1]
In 2010 and 2011, two rotationallightcurves ofGefion were obtained from photometric observations in the R-band by astronomers at thePalomar Transient Factory in California . Lightcurve analysis gave arotation period of 2.900 and 3.087 hours with a brightness amplitude of 0.22 and 0.20magnitude, respectively (U=2/2).[9]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Gefion measures between 6.965 and 7.016 kilometers in diameter and its surface has analbedo between 0.2489 and 0.252.[6][7] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and consequently calculates a much larger diameter of 12.62 kilometers based on anabsolute magnitude of 13.22.[8]
Thisminor planet was named afterGefjon a goddess in Norse mythology. It is also named for theGefion Fountain in Copenhagen, Denmark. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 117).[3]
