23 Thalia

23 Thalia (/θəˈlaɪ.ə/^{[lower-alpha 1]}) is a large main-belt asteroid. It was discovered by J. R. Hind on 15 December 1852, at the private observatory of W. Bishop, located in Hyde Park, London, England.^[5] Bishop named it after Thalia, the Muse of comedy and pastoral poetry in Greek mythology.^[6]

23 Thalia

A three-dimensional model of 23 Thalia based on its light curve.
Discovery
Discovered by	J. R. Hind
Discovery date	15 December 1852
Designations
MPC designation	(23) Thalia
Pronunciation	/θəˈlaɪ.ə/[1][lower-alpha 1]
Named after	Thalia
Alternative designations	1938 CL; 1974 QT2
Minor planet category	Main belt
Orbital characteristics
Epoch 14 June 2006 (JD 2453900.5)
Aphelion	484.663 Gm (3.240 AU)
Perihelion	301.483 Gm (2.015 AU)
Semi-major axis	393.073 Gm (2.628 AU)
Eccentricity	0.233
Orbital period (sidereal)	1555.679 d (4.26 a)
Mean anomaly	328.687°
Inclination	10.145°
Longitude of ascending node	67.228°
Argument of perihelion	59.311°
Physical characteristics
Dimensions	107.53 ± 2.2 km (IRAS)[2] 106.81 ± 3.23 km[3]
Mass	(1.96 ± 0.09) × 1018 kg[3]
Mean density	3.07 ± 0.31 g/cm3[3]
Synodic rotation period	12.312 h[2]
Geometric albedo	0.2536 (geometric)[4]
Spectral type	S [2]
Apparent magnitude	9.11 to 13.19
Absolute magnitude (H)	7.17[2]

It is categorized as an S-type asteroid consisting of mainly of iron- and magnesium-silicates. This the second most common type of asteroid in the main belt. Based on analysis of the light curve, the object has a sidereal rotation period of 0.513202 ± 0.000002 days. An ellipsoidal model of the light curve gives an a/b ratio of 1.28 ± 0.05.^[7]

With a semimajor axis of 2.628, the asteroid is orbiting between the 3:1 and 5:2 Kirkwood gaps in the main belt.^[8] Its orbital eccentricity is larger than the median value of 0.07 for the main belt, and the inclination is larger than the median of below 4°. But most of the main-belt asteroids have an eccentricity of no more than 0.4 and an inclination of up to 30°, so the orbit of 23 Thalia is not unusual for a main-belt asteroid.^[9]

Thalia has been studied by radar.^[10]

Notes

1. Stressed on the second syllable.

References

1. Webster, Noah (1884). A Practical Dictionary of the English Language.
2. "JPL Small-Body Database Browser: 23 Thalia". Jet Propulsion Laboratory. 30 April 2011. Retrieved 28 January 2012.
3. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
4. "Albedos Data Table". Planetary Science Institute. Archived from the original on 22 July 2012. Retrieved 3 November 2008.
5. Lardner, Dionysius (1858). Hand-books of natural philosophy and astronomy. Vol. 3. Philadelphia: Blanchard and Lea. p. 315. Retrieved 10 November 2009.
6. Schmadel, Lutz D. (2003). Dictionary of minor planet names (5th ed.). Springer. p. 17. ISBN 3-540-00238-3.
7. Lagerkvist, C.-I.; et al. (October 1995). "Physical studies of asteroids. XXIX. Photometry and analysis of 27 asteroids". Astronomy and Astrophysics Supplement. 113: 115–122. Bibcode:1995A&AS..113..115L.
8. Yeomans, Donald K. "Asteroid Main-Belt Distribution". NASA/Jet Propulsion Laboratoty. Retrieved 10 November 2009.
9. Williams, Gareth (3 April 2007). "Distribution of the Minor Planets". Minor Planets Center. Archived from the original on 21 March 2007. Retrieved 15 April 2007.
10. "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 30 October 2011.

External links

• 23 Thalia at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 23 Thalia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters