157 Dejanira

157 Dejanira is a main belt asteroid that was discovered by Alphonse Borrelly on 1 December 1875, and named after the warlike princess Deianira in Greek mythology (Δηιάνειρα in Greek). The Dejanira family of asteroids is named after it.

157 Dejanira

A three-dimensional model of 157 Dejanira based on its light curve.
Discovery[1]
Discovered by	A. Borrelly
Discovery date	1 December 1875
Designations
MPC designation	(157) Dejanira
Pronunciation	/dɛdʒəˈnaɪərə/[2]
Alternative designations	A875 XA; 1904 VB; 1978 TS1
Minor planet category	Main belt
Orbital characteristics[3][4]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	111.13 yr (40590 d)
Aphelion	3.0852 AU (461.54 Gm)
Perihelion	2.07801 AU (310.866 Gm)
Semi-major axis	2.58161 AU (386.203 Gm)
Eccentricity	0.19507
Orbital period (sidereal)	4.15 yr (1515.1 d)
Average orbital speed	18.36 km/s
Mean anomaly	312.135°
Mean motion	0° 14m 15.396s / day
Inclination	12.160°
Longitude of ascending node	62.070°
Argument of perihelion	46.282°
Earth MOID	1.11241 AU (166.414 Gm)
Jupiter MOID	2.16656 AU (324.113 Gm)
TJupiter	3.366
Physical characteristics
Dimensions	19.1 km
Mass	7.3×1015 kg
Mean density	2.0 g/cm3
Equatorial surface gravity	0.0053 m/s²
Equatorial escape velocity	0.0101 km/s
Synodic rotation period	15.825 h (0.6594 d)
Geometric albedo	0.10
Temperature	~173 K
Absolute magnitude (H)	11.2

Photometric observations of this asteroid were made in early 2009 at the Organ Mesa Observatory in Las Cruces, New Mexico. The resulting light curve shows a synodic rotation period of 15.825 ± 0.001 hours.^[5]