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1545 Thernöe

1545 Thernöe (prov. designation: 1941 UW) is an elongated background asteroid from the central region of the asteroid belt. It was discovered on 15 October 1941, by Finnish astronomer Liisi Oterma at Turku Observatory in Southwest Finland.[3] The uncommon K-type asteroid has a rotation period of 16.1 hours and measures approximately 18 kilometers (11 miles) in diameter. It was later named after Danish astronomer Karl August Thernöe.[2]

1545 Thernöe
Shape model of Thernöe from its lightcurve
Discovery[1]
Discovered byL. Oterma
Discovery siteTurku Obs.
Discovery date15 October 1941
Designations
(1545) Thernöe
Named after
Karl August Thernöe
(Danish astronomer)[2]
1941 UW · 1932 YD
1955 VV · 1957 HY
A906 FE · A915 CE
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc111.21 yr (40,619 days)
Aphelion3.4299 AU
Perihelion2.1097 AU
2.7698 AU
Eccentricity0.2383
4.61 yr (1,684 days)
84.917°
0° 12m 49.68s / day
Inclination2.9542°
51.800°
90.542°
Physical characteristics
16.12±5.02 km[4]
17.796±0.210 km[5]
18.656±0.376 km[6]
18.71±1.1 km[7]
19.37±0.31 km[8]
17.20±0.01 h[9]
17.20321±0.0001 h[10]
0.092±0.004[8]
0.0962±0.013[7]
0.097±0.012[6]
0.1063±0.0153[5]
0.13±0.10[4]
SMASS = K[1] · C[11]
11.76[4] · 11.8[11][5][6][7][8] · 11.9[1] · 12.09±0.45[12]

Orbit

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Thernöe orbits the Sun in the central main-belt at a distance of 2.1–3.4 AU once every 4 years and 7 months (1,684 days). Its orbit has an eccentricity of 0.24 and an inclination of 3° with respect to the ecliptic.[1] It was first identified as A906 FE at Heidelberg Observatory in 1906, extending the body's observation arc by 35 years prior to its official discovery observation at Turku.[3]

Naming

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This minor planet was named after Karl August Thernöe (1911–1987), Danish astronomer and celestial mechanic at Østervold Observatory in Copenhagen. He was also a popularizer of astronomy and director of IAU's Central Bureau for Astronomical Telegrams during 1950–1964.[2][13] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3930).[14]

Physical characteristics

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Spectral type

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In the SMASS taxonomy, Thernöe is classified as a rare K-type asteroid, a newly introduced subtype that belongs to the broader S-complex of stony bodies.[1] Conversely, CALL groups Thernöe into the carbonaceous C-complex.[11]

Rotation period and pole

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In December 2006, a rotational lightcurve of Thernöe was obtained from photometric observations by French amateur astronomer René Roy. Lightcurve analysis gave a well-defined rotation period of 17.20 hours with a brightness variation of 0.76 magnitude (U=3).[9] The high lightcurve-amplitude of 0.76 indicates that the body has a non-spheroidal shape.

A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring period of 17.20321 hours, as well as a spin axis of (164.0°, −5.0°) in ecliptic coordinates (λ, β).[10]

Diameter and albedo

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According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Thernöe measures between 16.12 and 19.37 kilometers in diameter and its surface has an albedo between 0.092 and 0.13.[4][5][6][7][8] The Collaborative Asteroid Lightcurve Link (CALL) adopts the results obtained by IRAS, that is, an albedo of 0.0962 and diameter of 18.71 kilometers with an absolute magnitude of 11.8.[11]

References

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  1. ^ a b c d e f g "JPL Small-Body Database Browser: 1545 Thernoe (1941 UW)" (2017-06-05 last obs.). Jet Propulsion Laboratory. Retrieved 30 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1545) Thernöe". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 122. doi:10.1007/978-3-540-29925-7_1546. ISBN 978-3-540-00238-3.
  3. ^ a b c "1545 Thernoe (1941 UW)". Minor Planet Center. Retrieved 3 April 2017.
  4. ^ 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.
  5. ^ 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. S2CID 35447010.
  6. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. S2CID 46350317. Retrieved 3 April 2017.
  7. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 22 October 2019.
  8. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  9. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1545) Thernöe". Geneva Observatory. Retrieved 3 April 2017.
  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. S2CID 118427201. Retrieved 3 April 2017.
  11. ^ a b c d "LCDB Data for (1545) Thernöe". Asteroid Lightcurve Database (LCDB). Retrieved 3 April 2017.
  12. ^ 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. S2CID 53493339. Retrieved 3 April 2017.
  13. ^ Erik Høg (7 December 2016). "Young astronomer in Denmark 1946 to 1958". Nuncius Hamburgensis. 38. arXiv:1512.01924. Bibcode:2015arXiv151201924H.
  14. ^ Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. Bibcode:2009dmpn.book.....S. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.
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