Eta
2 Doradus,
Latinized from η
2 Doradus, is a
star
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make ...
in the southern
constellation of
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 dolphinfish (''Coryphaena hippurus''), which is known as ''dorado'' in Spanish, alt ...
. It is visible to the naked eye as a dim, reddish star with an
apparent visual magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...
of 5.01
[ It is about 580 light years from the Sun as shown by ]parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby object ...
, and its net movement is one of receding, having a radial velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection ...
of +34.5 km/s.[ It is ]circumpolar
Circumpolar may refer to:
* Antarctic region
** Antarctic Circle
** the Antarctic Circumpolar Current
** Subantarctic
** List of Antarctic and subantarctic islands
** Antarctic Convergence
** Antarctic Circumpolar Wave
** Antarctic Ocean
* Arctic ...
south of latitude S.[
This object is an M-type ]giant star
A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...
, with its stellar classification
In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting t ...
being M2.5III.[ It has left the ]main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...
after exhausting its core hydrogen and expanded to around . The star is radiating about 1200[ times the ]Sun's luminosity
The solar luminosity (), is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
One nomi ...
from its photosphere
The photosphere is a star's outer shell from which light is radiated.
The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...
, 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 3726 K.[
]
References
External links
* 2004. Starry Night Pro, Version 5.8.4. Imaginova Imaginova Corporation is a U.S. digital commerce company based in Watsonville, California. The company, which was started in 1999 as "Space.com" by CNN business anchor Lou Dobbs, later became known as Space Holdings Corp. Dan Stone became Presiden ...
. . www.starrynight.com
{{DEFAULTSORT:Eta2 Doradus
M-type giants
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Dorado
Doradus, Eta2
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