1400 Tirela

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1400 Tirela
Discovery [1]
Discovered by L. Boyer
Discovery site Algiers Obs.
Discovery date 17 November 1936
MPC designation (1400) Tirela
Named after
Charles Tirel [2]
(discoverer's friend)
1936 WA · 1930 UQ
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 86.96 yr (31,762 days)
Aphelion 3.8513 AU
Perihelion 2.4001 AU
3.1257 AU
Eccentricity 0.2322
5.53 yr (2,018 days)
0° 10m 42.24s / day
Inclination 15.631°
Physical characteristics
Dimensions 14.67±0.62 km[5]
15.697±0.285 km[6][7]
29.21 km (calculated)[3]
8 h (superseded)[a]
13.35384±0.00001 h[8]
13.356 h[9]
0.057 (assumed)[3]
C (assumed)[3]
11.3[7] · 11.4[1][3] · 11.50[5]

1400 Tirela, provisional designation 1936 WA, is an asteroid and the parent body of the Tirela family, located in the outer regions of the asteroid belt, approximately 16 kilometers in diameter. It was discovered on 17 November 1936, by French astronomer Louis Boyer at the Algiers Observatory in North Africa.[10] The asteroid was named after Charles Tirel, a friend of the discoverer.[2]

Orbit and classification[edit]

Tirela is the parent body of the Tirela family,[4] a fairly large asteroid family, also known as the Klumpkea family, after its largest member 1040 Klumpkea.[11]:23

It orbits the Sun in the outer main belt at a distance of 2.4–3.9 AU once every 5 years and 6 months (2,018 days). Its orbit has an eccentricity of 0.23 and an inclination of 16° with respect to the ecliptic.[1]

The asteroid was first identified as 1930 UQ at Lowell Observatory in October 1930. The body's observation arc also begins at Lowell Observatory, with a precovery taken the night before its first identification.[10]

Physical characteristics[edit]

is an assumed C-type asteroid,[3] although the overall spectral type of the Tirela family is that of an S-type.[11]:23

Rotation period and poles[edit]

In the early 2000s, a rotational lightcurve of Tirela was obtained from photometric observations by a group of Hungarian astronomers. Lightcurve analysis gave a rotation period of 13.356 hours with a brightness amplitude of 0.55 magnitude (U=2),[9] superseding the result from a previous observation that gave a period of 8 hours.[a]

A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring sidereal period of 13.35384 hours, as well as two spin axis of (58.0°, −80.0°) and (297.0°, −41.0°) in ecliptic coordinates (λ, β).[8]

Diameter and albedo[edit]

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Tirela measures between 14.67 and 15.697 kilometers in diameter and its surface has an albedo between 0.216 and 0.227.[5][6][7]

The Collaborative Asteroid Lightcurve Link assumes an standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 29.21 kilometers based on an absolute magnitude of 11.4.[3]


This minor planet was named after Charles Tirel a friend of discoverer Louis Boyer-[2] The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 127).[2]


  1. ^ a b Lightcurve (not published) on Behrend website from 2001-07-03: rotation period 8 hours with a brightness amplitude of 0.25 mag. Quality code of 2. Summary figures for (1400) Tirela at LCDB


  1. ^ a b c d "JPL Small-Body Database Browser: 1400 Tirela (1936 WA)" (2017-09-30 last obs.). Jet Propulsion Laboratory. Retrieved 25 October 2017. 
  2. ^ a b c d Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1400) Tirela. Springer Berlin Heidelberg. p. 113. ISBN 978-3-540-00238-3. Retrieved 25 October 2017. 
  3. ^ a b c d e f g "LCDB Data for (1400) Tirela". Asteroid Lightcurve Database (LCDB). Retrieved 25 October 2017. 
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 25 October 2017. 
  5. ^ 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 25 October 2017. 
  6. ^ 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:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 25 October 2017. 
  7. ^ 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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 25 October 2017. 
  8. ^ 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:1601.02909Freely accessible. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 25 October 2017. 
  9. ^ a b Székely, P.; Kiss, L. L.; Szabó, Gy. M.; Sárneczky, K.; Csák, B.; Váradi, M.; et al. (August 2005). "CCD photometry of 23 minor planets" (PDF). Planetary and Space Science. 53 (9): 925–936. arXiv:astro-ph/0504462Freely accessible. Bibcode:2005P&SS...53..925S. doi:10.1016/j.pss.2005.04.006. Retrieved 25 October 2017. 
  10. ^ a b "1400 Tirela (1936 WA)". Minor Planet Center. Retrieved 25 October 2017. 
  11. ^ a b Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families" (PDF). Asteroids IV: 297–321. arXiv:1502.01628Freely accessible. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. Retrieved 25 October 2017. 

External links[edit]