Theta Doradus, Latinized from θ Doradus, is a solitary star in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Dorado Dorado (, ) is a constellation in the Southern Sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the mahi-mahi (''Coryphaena hippurus''), which is known as ''dorado'' ("golden") in Sp ...

. Based upon an annual parallax shift of 6.64 mas as seen from Earth, it is located around 540

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. With an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of +4.82, the star is bright enough to be faintly visible to the naked eye. This is an

evolved Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

orange-hued K-type

giant star A giant star has a substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsp ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of , where the suffix indicates it is a CN star, a cool giant showing unusually strong CN

bands Bands may refer to: * Bands (song), song by American rapper Comethazine * Bands (neckwear), form of formal neckwear * Bands (Italian Army irregulars) Bands () was an Italian military term for Irregular military, irregular forces, composed of nati ...

in its spectrum. With an age of around 1.17 billion years, it has an estimated 2.23 times the

mass of the Sun The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

and has expanded to about 36 times the

Sun's radius Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...

. It is radiating 427 times the

solar luminosity The solar luminosity () is a unit of radiant flux (Power (physics), power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxy, galaxies and other celestial objects in terms of the output of ...

from its

photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 4,320 K.

Naming

In the Chinese astronomical adaptation of the European southern hemisphere constellations, (), meaning '' White Patches Attached'', refers to an asterism consisting of θ Doradus and α Reticuli. Consequently, θ Doradus itself is known as (, .)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 27 日

References

{{DEFAULTSORT:Theta Doradus K-type giants Dorado Doradus, Theta Durchmusterung objects 034649 024372

1744 Events January–March * January 6 – The Royal Navy ship ''Bacchus'' engages the Spanish Navy privateer ''Begona'', and sinks it; 90 of the 120 Spanish sailors die, but 30 of the crew are rescued. * January 24 – The ...