161 Athor

161 Athor is an M-type Main belt asteroid that was discovered by James Craig Watson on April 19, 1876, at the Detroit Observatory^[1] and named after Hathor, an Egyptian fertility goddess. It is the namesake of a proposed Athor asteroid family, estimated to be ~3 billion years old.^[12]

161 Athor

A three-dimensional model of 161 Athor based on its light curve.
Discovery[1]
Discovered by	James Craig Watson
Discovery site	Detroit Observatory
Discovery date	19 April 1876
Designations
MPC designation	(161) Athor
Pronunciation	/ˈæθər/,[2] /ˈɑːθər/[3]
Named after	Hathor
Alternative designations	A876 HA; 1899 TA; 1961 PF; 1973 YN4
Minor planet category	Main belt[4]
Orbital characteristics[4][5]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	116.50 yr (42551 d)
Aphelion	2.70593 AU (404.801 Gm)
Perihelion	2.05285 AU (307.102 Gm)
Semi-major axis	2.37939 AU (355.952 Gm)
Eccentricity	0.137237
Orbital period (sidereal)	3.67 yr (1340.6 d)
Mean anomaly	348.807°
Mean motion	0° 16m 6.737s / day
Inclination	9.05986°
Longitude of ascending node	18.6090°
Time of perihelion	2024-Jan-13
Argument of perihelion	295.007°
Physical characteristics
Dimensions	44.19±3.3 km[4] Mean diameter[6] 47.0±0.2 km circular fit[7]
Synodic rotation period	7.280 h (0.3033 d)[4] 7.281 ± 0.001 hours[8] 7.288 ± 0.007 hours[9]
Geometric albedo	0.1980±0.033[4][6]
Spectral type	M[10]
Absolute magnitude (H)	9.15[4][11]

Photometric observations of the minor planet in 2010 gave a rotation period of 7.2798±0.0001 h with an amplitude of 0.19±0.02 in magnitude. This result is consistent with previous determinations.^[13] An occultation by Athor was observed, on October 15, 2002, showing an estimated diameter of 47.0 kilometres (29.2 mi).^[7] The spectra is similar to that of carbonaceous chondrites, with characteristics of ferric oxides and little or no hydrated minerals.^[14]