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 | |
| 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) |
| Mass | 1.2×1018 kg |
|
Mean density
|
3.21 ± 0.92 g/cm³ |
| 0.0252 m/s² | |
| 0.0476 km/s | |
| 0.5113 d (12.27 h) | |
| Albedo | 0.1715 |
| Temperature | ~173 K |
|
Spectral type
|
S |
| 9.89 to 13.51 | |
| 7.76 | |
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.
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.
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 with a density of 3.21 g/cm³.
...
Wikipedia