Discovered by R. Luther Pronunciation /ˈθiːtᵻs/ THEE-tis Adjectives Thetidian Discovered 17 April 1852 | Discovery date April 17, 1852 Minor planet category Main belt Orbital period 1,418 days Orbits Sun | |
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Alternative names A913 CA; A916 YF;1954 SO1 Similar Robert Luther discoveries, Other celestial objects | ||
Asteroid 17 thetis
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.
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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.
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 with a density of 3.21 g/cm³.