Iota Draconis (ι Draconis, abbreviated Iota Dra, ι Dra), also named Edasich , is a star in the northern circumpolar constellation of Draco.
A visually unremarkable star of apparent magnitude 3.3, in 2002 it was discovered to have a planet orbiting it (designated Iota Draconis b, later named Hypatia).
From parallax 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.
On discovery the planet was designated Iota Draconis b (or Edasich b).
It bore the traditional name Edasich, derived from the Arabic ' 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 organized a Working Group on Star Names (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 launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars.
IAU.org.
9 July 2014 The process involved public nomination and voting for the new names.NameExoWorlds The Process In December 2015, the IAU announced the winning name was Hypatia for this planet.Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
The winning name was submitted by Hypatia, a student society of the Physics Faculty of the Universidad Complutense de Madrid, Spain.
Hypatia was a famous Greek astronomer, mathematician, and philosopher.NameExoWorlds The Approved Names
In Chinese,  (), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of Iota Draconis, Theta Draconis, Eta Draconis, Zeta Draconis, Upsilon Draconis, 73 Draconis, Gamma Draconis and 23 Cassiopeiae. 中國星座神話
, written by 陳久金.
Published by 台灣書房出版有限公司, 2005, .
Consequently, the Chinese name for Iota Draconis itself is  (, .), 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum.
Accessed on line November 23, 2010.
representing  (), meaning Left Pivot.
English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name , Hong Kong Space Museum.
Accessed on line November 23, 2010. 左樞 (Zuǒshū)
is westernized into Tsao Choo by R.H. Allen with the same meaning Star Name - R.H. Allen p. 210 Properties
Edasich is larger and more massive than the Sun, with 1.8 times the mass and nearly 12 times the radius.
The spectrum matches a stellar classification of K2 III, indicating this is an evolved star that has exhausted the supply of hydrogen at its core and left the main sequence 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 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 of 70μm 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 Units, 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.
References
External links
SIMBAD: HD 137759 -- Variable Star
Extrasolar Planets Encyclopaedia: Notes for star HIP 75458
SolStation: Edasich/Iota Draconis
