164 Eva
164 Eva is a main-belt asteroid that was discovered by the French brothers Paul Henry and Prosper Henry on July 12, 1876, in Paris. The reason the name Eva was chosen remains unknown, though Karl Ludwig Littrow suspected a "worldly origin" ("Mit dem Namen könnten wir wie bei Miriam wieder den biblischen Boden zu betreten glauben, wenn wir bei diesem Entdecker nicht an Taufen weltlichen Ursprungs gewöhnt wären"). The orbital elements for 164 Eva were published in 1877 by American astronomer Winslow Upton. It is categorized as a C-type asteroid and is probably composed of primitive carbonaceous chondritic materials.
3D convex shape model of 164 Eva | |
| Discovery | |
|---|---|
| Discovered by | P. P. Henry |
| Discovery site | Paris |
| Discovery date | 12 July 1876 |
| Designations | |
MPC designation | (164) Eva |
| Pronunciation | /ˈiːvə/ |
Named after | Unknown |
Alternative designations | A876 NA |
Minor planet category | Main belt |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 118.93 yr (43438 d) |
| Aphelion | 3.5444 AU (530.23 Gm) |
| Perihelion | 1.7188 AU (257.13 Gm) |
Semi-major axis | 2.6338 AU (394.01 Gm) |
| Eccentricity | 0.34577 |
Orbital period (sidereal) | 4.27 yr (1561.2 d) |
Mean anomaly | 219.5472° |
Mean motion | 0° 13m 50.128s / day |
| Inclination | 24.4564° |
Longitude of ascending node | 76.8519° |
| 283.9561° | |
| Earth MOID | 0.882286 AU (131.9881 Gm) |
| Jupiter MOID | 2.44116 AU (365.192 Gm) |
| TJupiter | 3.191 |
| Physical characteristics | |
| Dimensions | 104.87±1.9 km 101.77 ± 3.61 km |
| Mass | (9.29 ± 7.76) × 1017 kg |
Mean density | 1.68 ± 1.41 g/cm3 |
Equatorial surface gravity | 2.249 cm/s (mean) |
Equatorial escape velocity | 4.857 cm/s (mean) |
Synodic rotation period | 13.66 h (0.569 d) 13.672 h |
| 0.0447±0.002 | |
| Temperature | 170 K (mean) |
| C | |
| 8.89, 8.84 | |
Photometric observations of this asteroid at the Palmer Divide Observatory in Colorado Springs, Colorado, during 2008 gave a light curve with a period of 13.672 ± 0.003 hours and a small brightness variation of 0.04 ± 0.01 in magnitude. This is consistent with a previous study reported in 1982 that listed a period estimate of 13.66 hours.
Between 2000 and 2021, 164 Eva has been observed to occult fourteen stars.
With a perihelion of 1.718 AU 164 Eva is the closest asteroid over 100 kilometers to approach the orbit of Mars. Its closest approach is about 0.05 AU or about 19.5 lunar distances.