_Hedera.png) Modelled shape ofHedera from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 25 January 1933 |
| Designations | |
| (1251) Hedera | |
| Pronunciation | /ˈhɛdərə/[2] |
Named after | Hedera(a.k.a. "Ivy")[3] |
| 1933 BE · 1929 CD1 1931 TJ2 · 1975 NW1 A907 GD · A915 CA | |
| main-belt[1][4] · (middle) background[5] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 102.80 yr (37,548 days) |
| Aphelion | 3.1452AU |
| Perihelion | 2.2884 AU |
| 2.7168 AU | |
| Eccentricity | 0.1577 |
| 4.48yr (1,636 days) | |
| 55.862° | |
| 0° 13m 12.36s / day | |
| Inclination | 6.0489° |
| 140.65° | |
| 217.52° | |
| Physical characteristics | |
| 13.239±0.150 km[6][7] 44.22 km(calculated)[4] | |
| 15.015±0.010 h[8] 19.9000±0.0002 h[9] 19.9020±0.0001 h[10] 19.9020±0.0002 h[11] 19.915±0.005 h[12] 19.915±0.007 h[12] 19.985±0.002 h[13] | |
| 0.057(assumed)[4] 0.636±0.050[6][7] | |
| Tholen =E[1] SMASS =X[1] E[7][14] · C(SDSS-MFB)[4] B–V = 0.689[1] U–B = 0.233[1] | |
| 10.5[1][4][7] · 10.67±0.28[15] | |
1251 Hedera (prov. designation:1933 BE) is abackground asteroid from the central regions of theasteroid belt, approximately 13 kilometers (8 miles) in diameter. It was discovered on 25 January 1933, by German astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory in southwest Germany.[16] The asteroid was named for the climbing plantHedera, commonly known as "ivy".[3]
Hedera is a non-family asteroid from the main belt'sbackground population.[5] It orbits the Sun in thecentral asteroid belt at a distance of 2.3–3.1 AU once every 4 years and 6 months (1,636 days;semi-major axis of 2.72 AU). Its orbit has aneccentricity of 0.16 and aninclination of 6° with respect to theecliptic.[1] The asteroid was first observed asA907 GD at Heidelberg in April 1907. The body'sobservation arc begins at Heidelberg, the night after its official discovery observation.[16]
Thisminor planet was named after the evergreen woody plantHedera ("ivy") a genus of climbing or ground-creeping woody plants in thearalia family (ivy family). Thenaming was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 115).[3]
Due to his many discoveries,Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between(1009) and(1200). This list also contained a sequence of 28 asteroids, starting with1054 Forsytia, that were all named after plants, in particularflowering plants(also see list of minor planets named after animals and plants).[17]
Hedera is anE-type andX-type asteroid in theTholen andSMASS classification, respectively.[1]
Several rotationallightcurves ofHedera have been obtained from photometric observations since 2007.[8][9][12][13] Best-rated lightcurve byJulian Oey at Kingsgrove and Leura observatories, Australia, gave arotation period of 19.9000 hours with a consolidated brightness amplitude between 0.41 and 0.61magnitude (U=3-).[4][9]
Modeled photometric data from the Lowell Photometric Database (LPD) and the robotic BlueEye600 Observatory, gave a concurring period of 19.9020 hours,[10][11] Both studies determined twospin axes of (124.0°, −70.0°) and (266.0°, −62.0°), as well as (271.0°, −53.0°) and (115.0°, −62.0°) inecliptic coordinates (λ, β).[10][11]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Hedera measures 13.239 kilometers in diameter and its surface has analbedo of 0.636.[6][7]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo forcarbonaceous asteroids of 0.057 and consequently calculates a larger diameter of 44.22 kilometers based on anabsolute magnitude of 10.50.[4]
