17 Thetis
Star field showing asteroid Thetis in the center
|
|
| Discovery | |
|---|---|
| Discovered by | R. Luther |
| Discovery date | April 17, 1852 |
| Designations | |
| Pronunciation | /ˈθiːtᵻs/ THEE-tis |
|
Named after
|
Thetis |
| A913 CA; A916 YF; 1954 SO1 |
|
| Main belt | |
| Adjectives | Thetidian |
| Orbital characteristics[1] | |
| Epoch October 22, 2004 (JD 2453300.5) | |
| Aphelion | 419.069 Gm (2.801 AU) |
| Perihelion | 319.991 Gm (2.139 AU) |
| 369.530 Gm (2.470 AU) | |
| Eccentricity | 0.134 |
| 1418.027 d (3.88 a) | |
|
Average orbital speed
|
18.87 km/s |
| 38.435° | |
| Inclination | 5.587° |
| 125.622° | |
| 135.906° | |
| Physical characteristics | |
| Dimensions | 90 ± 3.7 km (IRAS)[1] |
| Mass | 1.2×1018 kg[2][3] |
|
Mean density
|
3.21 ± 0.92 g/cm³[2] |
| 0.0252 m/s² | |
| 0.0476 km/s | |
| 0.5113 d (12.27 h)[1][4] | |
| Albedo | 0.1715[1][5] |
| Temperature | ~173 K |
|
Spectral type
|
S[1] |
| 9.89 to 13.51[6] | |
| 7.76[1] | |
17 Thetis is a large main-belt asteroid that was discovered by R. Luther on April 17, 1852. It was his first asteroid discovery. The name comes from Thetis, the mother of Achilles in Greek mythology.[7]
One Thetidian stellar occultation was observed from Oregon in 1999. However, the event was not timed.
The spectrum of this object indicates that it is an S-type asteroid with both low and high calcium forms of pyroxene on the surface, along with less than 20% olivine. The high-calcium form of pyroxene forms 40% or more of the total pyroxene present, indicating a history of igneous rock deposits. This suggests that the asteroid underwent differentiation by melting, creating a surface of basalt rock.[8]
Mass
The mass of Thetis has been calculated from perturbations by 4 Vesta and 11 Parthenope. In 2007, Baer and Chesley calculated Thetis to have a mass of 1.2×1018 kg[2][3] with a density of 3.21 g/cm³.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 (Mass of Thetis 0.00617 / Mass of Ceres 4.75) * Mass of Ceres 9.43E+20 = 1.224E+18
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ apmag 9.89 (1977-Jul-25) to 13.51 (1963-Aug-02) JPL Horizons daily output for 1950 to 2099
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
 |
Wikimedia Commons has media related to 17 Thetis. |
- JPL Ephemeris
- Lua error in package.lua at line 80: module 'strict' not found. (displays Elong from Sun and V mag for 2011)
- 2011-Apr-22 Occultation (Durech Model) / (2011 Asteroidal Occultation Results for North America)
