1061 Paeonia

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1061 Paeonia
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date10 October 1925
MPC designation(1061) Paeonia
Named after
peony (flowering plant)[2]
1925 TB · 1925 XB
1936 SM · 1942 XD
main-belt[1][3] · (outer)
Themis[4] · background[5]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc91.72 yr (33,502 d)
Aphelion3.7986 AU
Perihelion2.4505 AU
3.1245 AU
5.52 yr (2,017 d)
0° 10m 42.6s / day
Physical characteristics
Mean diameter
17.95 km (calculated)[4]
18.63±5.52 km[6]
23.092±0.151 km[7][8]
h (at least)[9]
7.9971±0.0001 h[a]
7.99710±0.00001 h[10]
0.08 (assumed)[4]
Tholen = C[3][4]
B–V = 0.676[3]
U–B = 0.337[3]
11.80[6] · 12.01±0.29[11]

1061 Paeonia, provisional designation 1925 TB, is a carbonaceous background asteroid from the outer regions of the asteroid belt, approximately 19 km (12 mi) in diameter. It was discovered on 10 October 1925, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Heidelberg, Germany.[1] The C-type asteroid has a rotation period of 8 hours and is likely very elongated.[4] It was named after the flowering plant Paeonia, commonly known as peony.[2]

Orbit and classification[edit]

Paeonia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[5] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Themis family (602), a very large family of carbonaceous asteroids, named after 24 Themis.[4]

It orbits the Sun in the outer 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 an eccentricity of 0.22 and an inclination of 2° with respect to the ecliptic.[3] The asteroid was first observed at the Simeiz Observatory in September 1925. The body's observation arc begins at Yerkes Observatory in November 1925, or one month after its official discovery observation at Heidelberg.[1]

Physical characteristics[edit]

In the Tholen classification, Paeonia is a common, carbonaceous C-type asteroid,[3][4] which agrees with the overall spectral type for the Themistians.[12]:23

Rotation period and pole[edit]

In December 1986, a rotational lightcurve of Paeonia was obtained from photometric observations by American physicist Frederick Pilcher at Illinois College. Lightcurve analysis gave a rotation period of at least 6 hours with a brightness amplitude of 0.5 magnitude (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.[9] In 2014, Pilcher revisited Paeonia 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 a spin axis at (155.0°, −50.0°) in ecliptic coordinates (λ, β).[10]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Paeonia measures between 18.63 and 23.092 kilometers in diameter and its surface has an albedo between 0.048 and 0.09.[6][7][8] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.08 and calculates a diameter of 17.95 kilometers based on an absolute magnitude of 12.09.[4]


This minor planet was named after the genus of flowering plants, Paeonia, which comprises all perennial peony plants. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 101).[2]

Reinmuth's flowers[edit]

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 with 1054 Forsytia, that were all named after plants, in particular flowering plants (also see list of minor planets named after animals and plants).[13]


  1. ^ a b Pilcher (2014) lightcurve plot of (1061) Paeonia period 7.9971±0.0001 hours with a brightness amplitude of 1.00 mag. Observation from 27 November to 29 December 2014. Quality code of n/a. List of Pilcher's lightcurve plots at the ASLC-website


  1. ^ a b c d "1061 Paeonia (1925 TB)". Minor Planet Center. Retrieved 21 March 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1061) Paeonia". Dictionary of Minor Planet Names – (1061) Paeonia. Springer Berlin Heidelberg. p. 91. doi:10.1007/978-3-540-29925-7_1062. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g h "JPL Small-Body Database Browser: 1061 Paeonia (1925 TB)" (2017-07-01 last obs.). Jet Propulsion Laboratory. Retrieved 21 March 2018.
  4. ^ a b c d e f g h i "LCDB Data for (1061) Paeonia". Asteroid Lightcurve Database (LCDB). Retrieved 21 March 2018.
  5. ^ a b "Asteroid 1061 Paeonia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 28 October 2019.
  6. ^ a b c d Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 21 March 2018.
  7. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 21 March 2018.
  8. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
  9. ^ a b Pilcher, F. (September 1987). "General Report of Position Observations by the ALPO Minor Planets Section for the Year 1986". The Minor Planet Bulletin. 14.: 23. Bibcode:1987MPBu...14...23P. Retrieved 21 March 2018.
  10. ^ a b Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: 6. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 21 March 2018.
  11. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 21 March 2018.
  12. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
  13. ^ Schmadel, Lutz D. (2007). "(1054) Forsytia". Dictionary of Minor Planet Names – (1054) Forsytia. Springer Berlin Heidelberg. p. 90. doi:10.1007/978-3-540-29925-7_1055. ISBN 978-3-540-00238-3.

External links[edit]