Iota Draconis (ι Draconis, abbreviated Iota Dra, ι Dra), also named Edasich ,
is a
star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
in the northern
circumpolar constellation
A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest po ...
of
Draco
Draco is the Latin word for serpent or dragon.
Draco or Drako may also refer to:
People
* Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived
* D ...
. A visually unremarkable star of
apparent 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 li ...
3.3,
[ in 2002 it was discovered to have a planet orbiting it] (designated Iota Draconis b, later named Hypatia). From 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 objects ...
measurements, this star is located at a distance of about from the Sun.[
]
Nomenclature
''ι Draconis'' ( Latinised to ''Iota Draconis'') is the star's Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...
. On discovery the planet was designated Iota Draconis b (or Edasich b).
It bore the traditional name ''Edasich'', derived from the Arabic
Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
' of Ulug Beg and the Dresden Globe, or 'Male hyena' by Kazwini, with ''Eldsich'' being recorded in the ''Century Cyclopedia''.[ In 2016, the ]International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
organized a Working Group on Star Names
The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...
(WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Edasich'' for this star.
In July 2014 the International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Hypatia for this planet. The winning name was submitted by Hypatia, a student society of the Physics Faculty of the Universidad Complutense de Madrid, Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
. Hypatia was a famous Greek astronomer, mathematician, and philosopher.
In Chinese
Chinese can refer to:
* Something related to China
* Chinese people, people of Chinese nationality, citizenship, and/or ethnicity
**''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation
** List of ethnic groups in China, people of va ...
, (), meaning '' Left Wall of Purple Forbidden Enclosure'', refers to an asterism consisting of Iota Draconis, Theta Draconis
Theta Draconis, a name Latinized from θ Draconis, is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye at night with an apparent visual magnitude of 4.12. Parallax measur ...
, Eta Draconis
Eta Draconis (η Draconis, abbreviated Eta Dra, η Dra) is a binary star in the northern circumpolar constellation of Draco. Despite having an apparent visual magnitude of only +2.73, it is the second-brightest star in this generally fain ...
, Zeta Draconis
Zeta Draconis (ζ Draconis, abbreviated Zet Dra, ζ Dra) is a binary star in the northern circumpolar constellation of Draco. With an apparent visual magnitude of +3.17, it is the fifth-brightest member of this generally faint constellati ...
, Upsilon Draconis
Upsilon Draconis (υ Dra) is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.83. Based upon an annual parallax shift of 9.48 mas ...
, 73 Draconis 73 may refer to:
* 73 (number)
* one of the years 73 BC, AD 73, 1973, 2073
* ''73'' (magazine), a United States-based amateur radio magazine
* 73 Best regards, a popular Morse code abbreviation
* '' No. 73'', a British 1980s children's TV show
*N ...
, Gamma Draconis
Gamma Draconis (γ Draconis, abbreviated Gamma Dra, γ Dra), formally named Eltanin , is a star in the northern constellation of Draco. Contrary to its gamma-designation (historically third-ranked), it is the brightest star in Draco at m ...
and 23 Cassiopeiae. Consequently, the Chinese name for Iota Draconis itself is (, en, the First Star of Left Wall of Purple Forbidden Enclosure.), representing (), meaning ''Left Pivot''. 左樞 (Zuǒshū) is westernized into ''Tsao Choo'' by R.H. Allen with the same meaning Star Name - R.H. Allen p. 210
/ref>
Properties
Edasich is larger and more massive than the Sun, with 1.8 times the mass and nearly 12 times the radius.[ The ]spectrum
A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...
matches 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 grati ...
of K2 III,[ indicating this is an ]evolved
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...
star that has exhausted the supply of hydrogen at its core and 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 ...
of stars like the Sun. With an expanded outer envelope, this giant star is radiating over 55 times the luminosity of the Sun 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 4,545 K.[ This temperature gives it an orange hue that is a characteristic of K-type stars.][ It is rotating at a leisurely rate, with a period of around 434 days.][ It is about 1.15 billion years old.][
In the past Iota Draconis has been suspected of variability. However, the star has been found to have a constant luminosity to within about 0.004 magnitudes. Hence, as of 2010, the variability remains unconfirmed.][ An excess emission of infrared radiation at a ]wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...
of 70μm
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
suggests the presence of a circumstellar disk of dust; what astronomers term a debris disk.[
]
Planetary system
The planetary companion discovered in 2002 was the first planet known to orbit a giant star. The habitable zone for this star lies in the range of 6.8–13.5 Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits t ...
s, placing this planet well inside.[ The alignment of this planet's orbit may make it directly detectable via the transit method.][ Another long-period planet or brown dwarf was discovered in 2021, and the true masses of both planets were measured via ]astrometry
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
His ...
.[
]
References
External links
''SIMBAD'': HD 137759 -- Variable Star
''Extrasolar Planets Encyclopaedia'': Notes for star HIP 75458
{{DEFAULTSORT:Iota Draconis
K-type giants
Draco (constellation)
Draconis, Iota
Draconis, 12
137759
075458
5744
BD+59 1654
Edasich
Planetary systems with two confirmed planets
Circumstellar disks
Suspected variables
J15245578+5857577