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145534 Jhongda
Discovery
Discovered by	T.-C. Yang; Q.-Z. Ye
Discovery site	Lulin Obs.
Discovery date	1 April 2006
Designations
MPC designation	(145534) Jhongda
Named after	National Central University; (Taiwanese University)
Alternative designations	2006 GJ
Minor planet category	main-belt · (middle); Merxia
Orbital characteristics
	Epoch 27 April 2019 (JD 2458600.5)
	Uncertainty parameter 0
Observation arc	25.91 yr (9,464 d)
Aphelion	3.0903 AU
Perihelion	2.3208 AU
Semi-major axis	2.7055 AU
Eccentricity	0.1422
Orbital period (sidereal)	4.45 yr (1,625 d)
Mean anomaly	262.51°
Mean motion	0° 13m 17.4s / day
Inclination	6.2031°
Longitude of ascending node	105.82°
Argument of perihelion	189.48°
Physical characteristics
Mean diameter	2.1 km (est. at 0.23); 3.54 km (calculated)
Synodic rotation period	4.49±0.040 h
Geometric albedo	0.057 (assumed); 0.23 (family albedo)
Spectral type	C (assumed); S (family based)
Absolute magnitude (H)	15.6

145534 Jhongda, provisional designation 2006 GJ, is an asteroid and member of the stony Merxia family, orbiting in the central region of the asteroid belt, approximately 2–3 kilometers (1–2 miles) in diameter. It was discovered by Taiwanese astronomers Yang Tingzhang and Ye Quanzhi at the Lulin Observatory on 1 April 2006. The likely elongated asteroid has a rotation period of 4.5 hours.^[6] It was named for the Taiwanese National Central University.^[1]

Orbit and classification

Jhongda is a member of the Merxia family (513),^[3]^[4] a large family of stony S-type asteroids named after its parent body 808 Merxia.^[8]^: 23 It orbits the Sun in the central main-belt at a distance of 2.3–3.1 AU once every 4 years and 5 months (1,625 days; semi-major axis of 2.71 AU). Its orbit has an eccentricity of 0.14 and an inclination of 6° with respect to the ecliptic.^[2] The first precovery was taken by Spacewatch in February 1992, extending the asteroid's observation arc by 14 years prior to its discovery at the Lulin Observatory.^[1]

Naming

This minor planet was named after the Taiwanese National Central University, which controls the discovering Lulin Observatory. "Jhongda" is the University's abbreviation in Mandarin Chinese.^[1] The official naming citation was published by the Minor Planet Center on 2 April 2007 (M.P.C. 59389).^[9]

Physical characteristics

In January 2014, a rotational lightcurve of Jhongda was obtained from photometric observation by astronomers at the Intermediate Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 4.490±0.040 hours with a high brightness variation of 0.67 in magnitude (U=2) indicative of an elongated, non-spherical shape.^[7] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 3.54 kilometers with an absolute magnitude of 15.98.^[6] Conversely, Jhongda measure only 2.1 kilometers for an albedo of 0.23,^[5] which is typical for the stony members of the Merxia family.^[8]^: 23

References

^ ^a ^b ^c ^d ^e ^f ^g "145534 Jhongda (2006 GJ)". Minor Planet Center. Retrieved 4 December 2018.
^ ^a ^b ^c ^d "JPL Small-Body Database Browser: 145534 Jhongda (2006 GJ)" (2018-01-23 last obs.). Jet Propulsion Laboratory. Retrieved 4 December 2018.
^ ^a ^b "Asteroid 145534 Jhongda". Small Bodies Data Ferret. Retrieved 4 December 2018.
^ ^a ^b "Asteroid (145534) Jhongda". AstDyS-2, Asteroids – Dynamic Site. Retrieved 4 December 2018.
^ ^a ^b "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 4 December 2018.
^ ^a ^b ^c ^d ^e "LCDB Data for (145534) Jhongda". Asteroid Lightcurve Database (LCDB). Retrieved 4 December 2018.
^ ^a ^b Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; et al. (August 2015). "Asteroid Spin-rate Study Using the Intermediate Palomar Transient Factory". The Astrophysical Journal Supplement Series. 219 (2): 19. arXiv:1506.08493. Bibcode:2015ApJS..219...27C. doi:10.1088/0067-0049/219/2/27. S2CID 17093124.
^ ^a ^b ^c 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. S2CID 119280014.
^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 December 2018.