145452 Ritona

145452 Ritona (provisional designation 2005 RN₄₃) is a large classical Kuiper belt object. It has an estimated diameter of 679+55
−73 km.^[6] It was discovered by Andrew Becker, Andrew Puckett and Jeremy Kubica on 10 September 2005 at Apache Point Observatory in Sunspot, New Mexico.

145452 Ritona

Hubble Space Telescope image of Ritona, taken in April 2010
Discovery[1]
Discovered by	A. C. Becker A. W. Puckett J. M. Kubica
Discovery site	APO
Discovery date	10 September 2005
Designations
MPC designation	(145452) Ritona
Pronunciation	/ˈrɪtənə/
Named after	Ritona
Alternative designations	2005 RN43
Minor planet category	TNO Cubewano[2][3] Extended (DES)[4]
Orbital characteristics[2]
Epoch 5 May 2025 (JD 2460800.5)
Uncertainty parameter 0
Observation arc	25930 days (70.99 yr)
Earliest precovery date	2 June 1954
Aphelion	42.667 AU (6.3829 Tm)
Perihelion	40.561 AU (6.0678 Tm)
Semi-major axis	41.614 AU (6.2254 Tm)
Eccentricity	0.025304
Orbital period (sidereal)	265.99 yr (97151.5 d)
Average orbital speed	0.0037°/d
Mean anomaly	347.83°
Mean motion	0° 0m 13.34s / day
Inclination	19.251°
Longitude of ascending node	187.01°
Time of perihelion	≈ 15 June 2029[5] ±9 days
Argument of perihelion	178.16°
Earth MOID	39.5672 AU (5.91917 Tm)
Jupiter MOID	35.6155 AU (5.32800 Tm)
TJupiter	5.446
Physical characteristics
Dimensions	679+55 −73 km[6]
Synodic rotation period	6.95 h (0.290 d)[2]
Sidereal rotation period	5.62 h[2]
Geometric albedo	0.107+0.029 −0.018[6]
Spectral type	IR–RR (red)[6] B–V=0.95±0.02[7] V–R=0.59±0.01[7] V–I=1.08±0.02[7]
Apparent magnitude	20.1[8]
Absolute magnitude (H)	3.89±0.05[6] 3.69[2]

Numbering and naming

The object received its minor planet catalog number of 145452 from the Minor Planet Center on 5 December 2006.^[9]: 160 On 21 July 2025, it was given the name Ritona, after the Celtic goddess of river fords.^[10]: 24

Classification

The Minor Planet Center (MPC) classifies it as a classical Kuiper belt object, or cubewano.^[3] But since this object has an inclination of 19.3°, the Deep Ecliptic Survey (DES) classifies it as scattered-extended.^[4]

It has been observed 119 times over thirteen oppositions, with precovery images back to 1954.^[2]

See also

• (144897) 2004 UX10
• (145451) 2005 RM43
• (145453) 2005 RR43
• (248835) 2006 SX368