115 Thyra is a fairly large and bright inner

main-belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

that was discovered by Canadian-American astronomer J. C. Watson on August 6, 1871 and was named for

Thyra Thyra, also known as Thorvi or Thyre, was a Danish queen, spouse of King Gorm the Old of Denmark, the first historically recognized King of Denmark, who reigned from to his death .

, the consort of King

Gorm the Old Gorm the Old ( da, Gorm den Gamle; non, Gormr gamli; la, Gormus Senex), also called Gorm the Languid ( da, Gorm Løge, Gorm den Dvaske), was ruler of Denmark, reigning from to his death or a few years later.Lund, N. (2020), p. 147

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

. Based upon its spectrum, it is categorized as a stony

S-type asteroid S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second ...

. Observations made between 1978 and 1981 produced a composite

light curve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

with two minima and maxima. However, a subsequent study in 1983 only found a single minima and maxima. A synodical rotation period of 7.241 hours was determined. This was confirmed by observations between 1995 and 2000. The changes in brightness and color indicate a surface with an uneven composition. The asteroid has a slightly elongated shape, with a ratio of 1.20 between the lengths of the major and minor axes. The orbital longitude and latitude of the asteroid pole in degrees is estimated to be (λ₀, β₀) = (68°, 23°). Measurements of the

thermal inertia In thermodynamics, a material's thermal effusivity, thermal inertia or thermal responsivity is a measure of its ability to exchange thermal energy with its surroundings. It is defined as the square root of the product of the material's thermal co ...

of 115 Thyra give a value of around 75 m⁻² K⁻¹ s^−1/2, compared to 50 for

lunar regolith Lunar soil is the fine fraction of the regolith found on the surface of the Moon. Its properties can differ significantly from those of terrestrial soil. The physical properties of lunar soil are primarily the result of mechanical disintegra ...

and 400 for coarse sand in an atmosphere.

References

External links

* * {{DEFAULTSORT:Thyra 000115 Discoveries by James Craig Watson Named minor planets 000115 000115 18710806