Theta Aquarii Explained

Theta Aquarii (θ Aquarii, abbreviated Theta Aqr, θ Aqr), officially named Ancha [1] (distinguish Ankaa, with the same pronunciation), is a star in the equatorial constellation of Aquarius. Visible to the naked eye at apparent magnitude 4.175, it is located at a distance of around 187abbr=offNaNabbr=off from the Sun. Since it is near the ecliptic it can be occulted by the Moon, or very rarely by planets.

Nomenclature

θ Aquarii (Latinised to Theta Aquarii) is the star's Bayer designation.

It bore the traditional name Ancha; Medieval Latin for "the haunch". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Ancha for this star on 12 September 2016, and it is now so included in the List of IAU-approved Star Names.[1]

In Chinese, Chinese: (Chinese: ), meaning Weeping, refers to an asterism consisting of Theta Aquarii and Rho Aquarii.[2] Consequently, the Chinese name for Theta Aquarii itself is Chinese: 泣二 (Chinese: Qì èr, English: the Second Star of Weeping).[3] Possibly, the name Lei, meaning "tears (weeping)" in Chinese, derives from the Chinese name for this star.[4]

Properties

Ancha belongs to the spectral class G8 with a luminosity class of III–IV suggesting that, at an age of 437 million years, this star is part way between the subgiant and giant stages of its evolution. Estimates of the star's mass range from 2.39 to 2.78 times the Sun's mass, with a radius of about 12 times that of the Sun. It is radiating from 72 to 83 times as much luminosity as the Sun from its enlarged outer envelope at an effective temperature of 4,864 K. At this heat, the star glows with the yellow hue of a G-type star.

External links

Notes and References

  1. Web site: Naming Stars . IAU.org . 16 December 2017.
  2. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, .
  3. 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.
  4. Web site: Star Names — Their Lore and Meaning . Richard Hinckley Allen . www.constellationsofwords.com.