Delta Eridani
Encyclopedia
Delta Eridani is a 3.54 magnitude star in the constellation of Eridanus
Eridanus (constellation)
Eridanus is a constellation. It is represented as a river; its name is the Ancient Greek name for the Po River. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is the sixth largest of the modern...

. It is also called Rana. The name Rana means "the frog" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...



In Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...

, , meaning Celestial Meadows
Hairy Head (Chinese constellation)
The Hairy Head mansion is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger.This mansion corresponds to the Pleiades in English.-Asterisms:...

, refers to an asterism consisting of δ Eridani, γ Eridani
Gamma Eridani
Gamma Eridani is a star in the constellation Eridanus. It has the traditional name Zaurak, which means "the boat."In Chinese, , meaning Celestial Meadows, refers to an asterism consisting of γ Eridani, δ Eridani, π Eridani, ε Eridani, ζ Eridani , η Eridani, π Ceti, τ1 Eridani, τ2 Eridani, τ3...

, π Eridani, ε Eridani
Epsilon Eridani
Epsilon Eridani is a star in the southern constellation Eridanus, along a declination 9.46° south of the celestial equator. This allows the star to be viewed from most of the Earth's surface. At a distance of 10.5 light years , it has an apparent magnitude of 3.73...

, ζ Eridani , η Eridani
Eta Eridani
Eta Eridani is a star in the constellation Eridanus. It has the traditional name Azha . The word Azha is a corruption of Persian آشيانه āšiyāne The nest...

, π Ceti
Pi Ceti
Pi Ceti is a Class B7, fourth-magnitude star in the constellation Cetus. Pi Ceti is a blue main-sequence star located about 440 light-years from Earth.-Name:...

, τ1 Eridani, τ2 Eridani
Tau2 Eridani
Tau2 Eridani is a star in the constellation Eridanus . It is one of a series of stars that share the Bayer designation Tau Eridani...

, τ3 Eridani, τ4 Eridani
Tau4 Eridani
Tau4 Eridani is a Class M3.5III, fourth-magnitude star in the constellation Eridanus. Tau4 Eridani is a binary star system consisting primarily of Class M components, the brightest component being a Class M giant of apparent magnitude 3.66, having a mass and luminosity many times greater than that...

, τ5 Eridani, τ6 Eridani, τ7 Eridani, τ8 Eridani and τ9 Eridani. Consequently, δ Eridani itself is known as

Structure

This star is relatively near to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

, at a measured distance of about 29 light years. It is sometime listed as a RS Canum Venaticorum
RS Canum Venaticorum variable
RS Canum Venaticorum variables are a type of variable star. They are close binary stars having active chromospheres which can cause large stellar spots. These spots are believed to cause variations in their observed luminosity...

-type variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

, but this is likely to be an error. (It is currently a suspected variable.) Rana is a sub-giant star that is near the end of its hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

-burning cycle and is now consuming helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...

. This has caused the star to expand and become hotter than a comparable main sequence star. As a sub-giant star it is subject to pulsations in its atmosphere.

Radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

 surveys of this star have thus far failed to discern any gas giant
Gas giant
A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...

s in orbit.

External links

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