Contents

173 Ino

173 Ino

Discovery[1]
Discovered by	A. Borrelly
Discovery site	Marseille
Discovery date	1 August 1877
Designations
MPC designation	(173) Ino
Pronunciation	/ˈaɪnoʊ/ EYE-noh[2]
Named after	Ἰνώ Īnṓ[3] (Greek mythology)
Alternative designations	A877 PA; 1922 SB
Minor planet category	main-belt[1][4] · (middle) Ino[5]
Adjectives	Inoan (/aɪˈnoʊən/ eye-NOH-ən)[6]
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	138.75 yr (50,678 d)
Aphelion	3.3142 AU
Perihelion	2.1708 AU
Semi-major axis	2.7425 AU
Eccentricity	0.2085
Orbital period (sidereal)	4.54 yr (1,659 d)
Mean anomaly	307.27°
Mean motion	0° 13m 1.2s / day
Inclination	14.197°
Longitude of ascending node	148.18°
Argument of perihelion	228.89°
Physical characteristics
Dimensions	c/a = 0.76±0.06[7]
Mean diameter	145±3 km[7] 119±27 km[8] 125.8±1.5 km[9] 148±42 km[10] 154.1±3.5 km[11] 160.6 km[12]
Mass	(2.2±1.3)×1018 kg[7] (4.79±3.11)×1018 kg[13]
Mean density	1.4±0.8 g/cm3[7] 2.23±1.47 g/cm3[13]
Synodic rotation period	5.93 h[14] 6.1±0.2 h[15] 6.106±0.001 h[15] 6.1088±0.0007 h[15] 6.11 h[16] 6.113±0.002 h[17] 6.11651 h[18] 6.15 h[19] 6.163 h[20]
Geometric albedo	0.061 (calculated)[7] 0.059[12] 0.06±0.02[10] 0.0642±0.003[11] 0.07±0.05[8] 0.096±0.018[9]
Spectral type	Tholen = C[4] SMASS = Xk[4] B–V = 0.705[4] U–B = 0.305[4]
Absolute magnitude (H)	7.66[4][9][10][11][12][21] 7.80±0.05[22] 7.90[8][23]

Ino (minor planet designation: 173 Ino) is a large asteroid and the parent body of the Ino family, located in the central regions of the asteroid belt, approximately 150 kilometers (93 miles) in diameter. It was discovered on 1 August 1877, by French astronomer Alphonse BorrellyatMarseille Observatory in southern France, and named after the queen Ino from Greek mythology.^[1][3] The dark Xk-type asteroid has a rotation period of 6.15 hours.^[21]

Ino is the parent body and namesake of the Ino family (522),^[5]anasteroid family in the intermediate main belt with nearly 500 known members.^[24]: 23 The adjectival form of the asteroid name is "Inoan".

It orbits the Sun in the central main-belt at a distance of 2.2–3.3 AU once every 4 years and 6 months (1,659 days; semi-major axis of 2.74 AU). Its orbit has an eccentricity of 0.21 and an inclination of 14° with respect to the ecliptic.^[4] The body's observation arc begins at Düsseldorf-Bilk Observatory in January 1879, five months after its official discovery observation at Marseilles.^[1]

In the Tholen classification, Ino is a common carbonaceous C-type, while in the SMASS classification it is a Xk-subtype that transitions between the X-type and uncommon K-type asteroids.^[4]

Multiple photometric studies of this asteroid were performed between 1978 and 2002. The combined data gave an irregular, asymmetrical light curve with a period of 6.163 ± 0.005 hours and a brightness variation of 0.10–0.15 in magnitude. The asteroid is rotating in a retrograde direction.^[18]

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 173 InoatAstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 173 Ino at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters