2064 Thomsen

2064 Thomsen (prov. designation: 1942 RQ) is a stony asteroid and Mars-crosser on an eccentric orbit, that measures approximately 13 kilometers (8.1 miles) in diameter. The asteroid was discovered by Finnish astronomer Liisi Oterma at Turku Observatory, Finland, on 8 September 1942.^[3] It was named after New Zealand astronomer Ivan Leslie Thomsen

2064 Thomsen

Shape model of Thomsen from its lightcurve
Discovery[1]
Discovered by	L. Oterma
Discovery site	Turku Obs.
Discovery date	8 September 1942
Designations
MPC designation	(2064) Thomsen
Named after	Ivan Leslie Thomsen (New Zealand astronomer)[2]
Alternative designations	1942 RQ · 1958 RO 1974 OK · 1977 FE3 1977 KA · A913 QB
Minor planet category	Mars-crosser[1][3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	74.50 yr (27,211 days)
Aphelion	2.8967 AU
Perihelion	1.4600 AU
Semi-major axis	2.1783 AU
Eccentricity	0.3298
Orbital period (sidereal)	3.22 yr (1,174 days)
Mean anomaly	142.30°
Mean motion	0° 18m 23.76s / day
Inclination	5.6946°
Longitude of ascending node	302.16°
Argument of perihelion	2.7479°
Earth MOID	0.4446 AU
Physical characteristics
Mean diameter	8.09±0.12 km[4] 13.59 km (derived)[5] 13.61±1.6 km (IRAS:2)[6]
Synodic rotation period	4.2267±0.0001 h[7] 4.233 h[8] 4.244023±0.000001 h[9] 4.253±0.005 h[10]
Geometric albedo	0.0549±0.015 (IRAS:2)[6] 0.0644 (derived)[5] 0.162±0.006[4]
Spectral type	SMASS = S[1] · S[5][11][12] B–V = 0.887[1] U–B = 0.524[1]
Absolute magnitude (H)	12.6[1] · 12.93[5][8] · 13.10[4][6][12] · 13.44±0.31[11]

Orbit and classification

The S-type asteroid orbits the Sun in the inner main-belt at a distance of 1.5–2.9 AU once every 3 years and 3 months (1,174 days). Its orbit has an eccentricity of 0.33 and an inclination of 6° with respect to the ecliptic.^[1]

Naming

This minor planet was named in memory of New Zealand astronomer Ivan Leslie Thomsen (1910–1969), director of the Carter Observatory, Wellington, from 1945 until he was appointed director of the Mount John University Observatory only two months before his death. He was an enthusiastic coordinator of New Zealand's astronomy and his efforts eventually led to the minor-planet observing program with the Carter Observatory 41-cm reflector. It was the 1977 rediscovery at the Carter Observatory that allowed this minor planet to be numbered. The official naming citation was published by the Minor Planet Center on 1 August 1978 (M.P.C. 4421).^[2][13]

Physical characteristics

Four rotational lightcurves gave a well-defined rotation period of 4.233 hours with a brightness variation of 0.62–0.69 magnitude (U=3/3/ .a./3)^{[7][8][9][10]} and an albedo of 0.055 and 0.16, as measured by the IRAS and Akari surveys, respectively.^[4][6]