_Paeonia.png) Modelled shape ofPaeonia from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 10 October 1925 |
| Designations | |
| (1061) Paeonia | |
| Pronunciation | /piːˈoʊniə/[2] |
Named after | peony(flowering plant)[3] |
| 1925 TB · 1925 XB 1936 SM · 1942 XD | |
| main-belt[1][4] · (outer) Themis[5] · background[6] | |
| Orbital characteristics[4] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 91.72yr (33,502 d) |
| Aphelion | 3.7986AU |
| Perihelion | 2.4505 AU |
| 3.1245 AU | |
| Eccentricity | 0.2157 |
| 5.52 yr (2,017 d) | |
| 249.51° | |
| 0° 10m 42.6s / day | |
| Inclination | 2.4993° |
| 90.923° | |
| 306.27° | |
| Physical characteristics | |
| 17.95 km(calculated)[5] 18.63±5.52 km[7] 23.092±0.151 km[8][9] | |
| 6 h(at least)[10] 7.9971±0.0001 h[a] 7.99710±0.00001 h[11] | |
| 0.048±0.007[8] 0.0483±0.0070[9] 0.08(assumed)[5] 0.09±0.06[7] | |
| Tholen =C[4][5] B–V = 0.676[4] U–B = 0.337[4] | |
| 11.80[7] · 12.01±0.29[12] 12.09[4][5][9] | |
1061 Paeonia, provisional designation1925 TB, is a carbonaceousbackground asteroid from the outer regions of theasteroid belt, approximately 19 km (12 mi) in diameter. It was discovered on 10 October 1925, by German astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory in Heidelberg, Germany.[1] TheC-type asteroid has arotation period of 8 hours and is likely very elongated.[5] It was named after the flowering plantPaeonia, commonly known aspeony.[3]
Paeonia is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[6] Based on osculating Keplerianorbital elements, the asteroid has also been classified as a member of theThemis family (602), a very largefamily of carbonaceous asteroids, named after24 Themis.[5]
It orbits the Sun in theouter asteroid belt at a distance of 2.5–3.8 AU once every 5 years and 6 months (2,017 days;semi-major axis of 3.12 AU). Its orbit has aneccentricity of 0.22 and aninclination of 2° with respect to theecliptic.[4] The asteroid was first observed at theSimeiz Observatory in September 1925. The body'sobservation arc begins atYerkes Observatory in November 1925, or one month after its official discovery observation at Heidelberg.[1]
Thisminor planet was named after the genus of flowering plants,Paeonia, which comprises all perennialpeony plants. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 101).[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).[13]
In theTholen classification,Paeonia is a common, carbonaceousC-type asteroid,[4][5] which agrees with the overallspectral type for the Themistians.[14]: 23
In December 1986, a rotationallightcurve ofPaeonia was obtained fromphotometric observations by American physicistFrederick Pilcher atIllinois College. Lightcurve analysis gave arotation period of at least 6 hours with a brightness amplitude of 0.5magnitude (U=2-). Only a lower limit could be determined due to the short observation period. The observer noted that the brightness variation occurred within 2 hours or less.[10] In 2014, Pilcher revisitedPaeonia at his Organ Mesa Observatory (G50) and measured a refined period of 7.9971 hours with an amplitude of 1.00 magnitude (U=n.a.), a strong indication for an elongated shape.[a]
A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave an identical sidereal period of 7.9971 hours, as well as aspin axis at (155.0°, −50.0°) inecliptic coordinates (λ, β).[11]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Paeonia measures between 18.63 and 23.092 kilometers in diameter and its surface has analbedo between 0.048 and 0.09.[7][8][9] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.08 and calculates a diameter of 17.95 kilometers based on anabsolute magnitude of 12.09.[5]
