1863 Antinous

1863 Antinous /ænˈtɪnoʊəs/, provisional designation 1948 EA, is a stony asteroid and near-Earth object, approximately 2–3 kilometers in diameter. It was discovered on 7 March 1948 by American astronomer Carl Wirtanen at Lick Observatory on the summit of Mount Hamilton, California.^[4] It was named after Antinous from Greek mythology.^[3]

1863 Antinous

Discovery[1]
Discovered by	C. A. Wirtanen
Discovery site	Lick Obs.
Discovery date	7 March 1948
Designations
MPC designation	(1863) Antinous
Pronunciation	/ænˈtɪnoʊəs/[2]
Named after	Antinous (Greek mythology)[3]
Alternative designations	1948 EA
Minor planet category	Apollo NEO[1][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	68.91 yr (25,168 days)
Earliest precovery date	5 March 1948
Aphelion	3.6293 AU
Perihelion	0.8895 AU
Semi-major axis	2.2594 AU
Eccentricity	0.6063
Orbital period (sidereal)	3.40 yr (1,240 days)
Mean anomaly	139.55°
Mean motion	0° 17m 24.72s / day
Inclination	18.398°
Longitude of ascending node	346.48°
Argument of perihelion	268.00°
Earth MOID	0.1836 AU (71.5 LD)
Physical characteristics
Dimensions	1.80 km (derived)[5] 2.1 km (Gehrels)[1] 3.16 km[6] 3.23 km[7]
Synodic rotation period	4.02 h[8] 4.386±0.004 h[9] 7.453±0.005 h[10] 7.4568±0.0017 h[a] 7.471±0.005 h[b]
Geometric albedo	0.10[7] 0.11±0.08[11] 0.24 (Gehrels)[1] 0.29 (derived)[5]
Spectral type	SU (Tholen) Sq (SMASS)[1] L[12] SU[5]
Absolute magnitude (H)	15.00[12] 15.14±0.03 (R)[a] 15.5[7] 15.54[1] 15.62[8] 15.639±0.058[5][13] 15.69±0.14[9]

Orbit and classification

Antinous is also classified as a Mars-crosser and Apollo asteroid. The SU/Sq-type asteroid orbits the Sun in the inner main-belt at a distance of 0.9–3.6 AU once every 3 years and 5 months (1,240 days). Its orbit has an eccentricity of 0.61 and an inclination of 18° with respect to the ecliptic.^[1]

It has an Earth Minimum orbit intersection distance (MOID) of 0.1836 AU. In the 20th century Antinous passed within 30 Gm of the Earth five times; it will do so only once in the 21st. The nearest distance increases each time, from 26 to 29 Gm.^{[citation needed]}

Physical characteristics

In the Tholen and SMASS taxonomic scheme, Antinous is characterized as a SU and Sq type, respectively, which are subtypes of the broader group of S-type asteroids.^[1] The Apollo asteroid has a rotation period of 7.46 hours and an albedo between 0.10 and 0.240,^{[1][6][7][11]}

Naming

This minor planet was named after Antinous from Greek mythology. Antinous was one of the many unwelcome suitors for Penelope's hand while her husband, Odysseus, was away on his travels (also see 201 Penelope and 1143 Odysseus). Antinous, being the most insolent of all, was the first to be killed by Odysseus on his return.^[3] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3935).^[14]

Notes

1. Pravec (1999) web: rotation period 7.4568±0.0017 hours with a brightness amplitude of 0.23 mag, and quality code: n.a.. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1863) Antinous
2. Warner (2016) web: rotation period 7.471±0.005 hours with a brightness amplitude of 0.33 mag, and quality code: 3. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1863) Antinous