1373 Cincinnati

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1373 Cincinnati
Discovery [1]
Discovered byE. Hubble
Discovery siteMount Wilson Obs.
Discovery date30 August 1935
MPC designation(1373) Cincinnati
Named after
Cincinnati Observatory[1]
1935 QN
main-belt[1] · (outer)[2][3]
Cybele[4] · ACO [5]
Orbital characteristics[2]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 0
Observation arc82.62 yr (30,176 d)
Aphelion4.4958 AU
Perihelion2.3457 AU
3.4208 AU
6.33 yr (2,311 d)
0° 9m 20.88s / day
Physical characteristics
Mean diameter
19.448±0.175 km[6][7]
19.751±0.165 km[8]
22.16±1.66 km[9]
5.2834±0.0002 h[10]
SMASS = Xk[11]

1373 Cincinnati, provisional designation 1935 QN, is an asteroid in a comet-like orbit from the Cybele region, located at the outermost rim of the asteroid belt, approximately 20 kilometers (12 miles) in diameter. It was the only asteroid discovery made by famous American astronomer Edwin Hubble, while observing distant galaxies at Mount Wilson Observatory in California on 30 August 1935.[1] The rather spherical X-type asteroid has a rotation period of 5.3 hours.[3] It was named for the Cincinnati Observatory.[1]

Orbit and classification[edit]

Cincinnati orbits the Sun in the outermost asteroid belt at a distance of 2.3–4.5 AU once every 6 years and 4 months (2,311 days; semi-major axis of 3.42 AU). Its orbit has an eccentricity of 0.31 and an inclination of 39° with respect to the ecliptic.[2] The body's observation arc begins with its official discovery observation at Mount Wilson in August 1935.[1]

Cincinnati, a non-family asteroid of the main belt's background population,[12] is located in the orbital region of the Cybele asteroid, the last outpost of an extended asteroid belt beyond the Hecuba-gap asteroids. Due to its high inclination, and contrary to all other Cybele asteroids, Cincinnati is the only one that is above the center of the ν6 secular resonance with Saturn.[4]:2 The asteroid's high inclination and eccentricity also results in a Tisserand's parameter (TJupiter) of 2.719, which makes it a true asteroid in cometary orbit (ACO) for having a TJupiter value below 3.[5]


Recommended by the Minor Planet Center, this minor planet was named after the Cincinnati Observatory, whose staff provided most of the orbit computations. The official naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 2116).[13]

Physical characteristics[edit]

In the SMASS classification, Cincinnati is a Xk-type, a subtype that transitions from the X-type to the uncommon K-type asteroids,[11] while the Wide-field Infrared Survey Explorer classifies it as a metallic M-type asteroid.[3][8] By 2014, Cincinnati is the only of three Cybele asteroids for which a spectral type has been determined; the other two are 522 Helga and 692 Hippodamia, an X- and S-type, respectively.[4]:3

Rotation period[edit]

In January 2018, a rotational lightcurve of Cincinnati was obtained from photometric observations by Henk de Groot.[10] Lightcurve analysis gave a rotation period of 5.2834±0.0002 hours and a brightness variation of 0.10 magnitude (U=2+).[10] The low brightness amplitude is indicative that is asteroid is rather spherical than elongated in shape.

Alternative period determinations were made by French amateur astronomer René Roy (5.274 h; Δ0.21 mag) in August 2004 (U=2).[10] Two more lightcurves were obtained by Brian Warner at this Palmer Divide Observatory in Colorado, United States, in August 2004 and August 2010, who measured a period of 4.930 and 5.28 hours with an amplitude of 0.11 and 0.14 magnitude, respectively.[14][15][a]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's WISE telescope, Cincinnati measures between 19.4 and 19.8 kilometers in diameter and its surface has an albedo of 0.15–0.16,[6][7][8] while the Japanese Akari satellite determined a diameter of 22.16 kilometers with an albedo of 0.12.[9] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 27.9 kilometers based on an absolute magnitude of 11.5.[3]


  1. ^ Lightcurve plot of (1373) Cincinnati, Palmer Divide Observatory (716), B. D. Warner (2010). Summary figures at the LCDB.


  1. ^ a b c d e f g "1373 Cincinnati (1935 QN)". Minor Planet Center. Retrieved 13 December 2018.
  2. ^ a b c d "JPL Small-Body Database Browser: 1373 Cincinnati (1935 QN)" (2018-04-23 last obs.). Jet Propulsion Laboratory. Retrieved 13 December 2018.
  3. ^ a b c d e "LCDB Data for (1373) Cincinnati". Asteroid Lightcurve Database (LCDB). Retrieved 13 December 2018.
  4. ^ a b c Carruba, V.; Nesvorný, D.; Aljbaae, S.; Huaman, M. E. (July 2015). "Dynamical evolution of the Cybele asteroids". Monthly Notices of the Royal Astronomical Society. 451 (1): 244–256. arXiv:1505.03745. Bibcode:2015MNRAS.451..244C. doi:10.1093/mnras/stv997.
  5. ^ a b Licandro, J.; Alvarez-Candal, A.; de León, J.; Pinilla-Alonso, N.; Lazzaro, D.; Campins, H. (April 2008). "Spectral properties of asteroids in cometary orbits" (PDF). Astronomy and Astrophysics. 481 (3): 861–877. Bibcode:2008A&A...481..861L. doi:10.1051/0004-6361:20078340. Retrieved 13 December 2018.
  6. ^ a b c d Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M. Retrieved 13 December 2018.
  7. ^ a b c Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
  8. ^ a b c d e f 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. (catalog)
  9. ^ 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. Retrieved 13 December 2018. (online, AcuA catalog p. 153)
  10. ^ a b c d Behrend, Raoul. "Asteroids and comets rotation curves – (1373) Cincinnati". Geneva Observatory. Retrieved 13 December 2018.
  11. ^ a b "Asteroid 1373 Cincinnati". Small Bodies Data Ferret. Retrieved 13 December 2018.
  12. ^ "Asteroid (1373) Cincinnati – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 25 May 2018.
  13. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 13 December 2018.
  14. ^ Warner, Brian D. (March 2005). "Lightcurve analysis for asteroids 242, 893, 921, 1373, 1853, 2120, 2448 3022, 6490, 6517, 7187, 7757, and 18108". The Minor Planet Bulletin. 32 (1): 4–7. Bibcode:2005MPBu...32....4W. ISSN 1052-8091.
  15. ^ Warner, Brian D. (January 2011). "Lightcurve Analysis at the Palmer Divide Observatory: 2010 June-September". The Minor Planet Bulletin. 38 (1): 25–31. Bibcode:2011MPBu...38...25W. ISSN 1052-8091.

External links[edit]