Kappa Aquarii
 Location of ι Aquarii (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 37m 45.38049s[1] |
| Declination | –04° 13′ 40.9939″[1] |
| Apparent magnitude (V) | 5.03[2] |
| Characteristics | |
| Spectral type | K2 III[3] |
| U−B color index | +1.16[2] |
| B−V color index | +1.142[4] |
| Astrometry | |
| Radial velocity (Rv) | +7.31 ± 0.16[4] km/s |
| Proper motion (μ) | RA: –69.23[1] mas/yr Dec.: –119.67[1] mas/yr |
| Parallax (π) | 15.25 ± 0.21[1] mas |
| Distance | 214 ± 3 ly (65.6 ± 0.9 pc) |
| Details | |
| Radius | 13[4] R☉ |
| Luminosity | 60[4] L☉ |
| Surface gravity (log g) | 2.5[4] cgs |
| Temperature | 4,581[4] K |
| Metallicity [Fe/H] | +0.14[4] dex |
| Rotational velocity (v sin i) | 3.8[4] km/s |
| Other designations | |
Kappa Aquarii (κ Aqr, κ Aquarii) is the Bayer designation for a double star in the equatorial constellation of Aquarius. It has the traditional name Situla, a Latin word meaning "bucket" or "water jar".[6] This system is visible to the naked eye, but it is faint at an apparent magnitude of 5.03.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to Kappa Aquarii is around 214 light-years (66 parsecs).[2]
This is most probably a wide binary star system.[7] The brighter component is a giant star with a stellar classification of K2 III.[3] It has exhausted the supply of hydrogen at its core and has expanded to 13[4] times the radius of the Sun. Kappa Aquarii is radiating 60[4] times the Sun's luminosity from its outer envelope at an effective temperature of 4,581 K,[4] giving it the orange-hued glow of a K-type star.[8]
The fainter companion star is located at an angular separation of 98.3 arcseconds and has an apparent magnitude of 8.8.[8]
In culture
In Chinese, 虛梁 (Xū Liáng), meaning Temple, refers to an asterism consisting of κ Aquarii, 44 Aquarii, 51 Aquarii and HD 216718.[9] Consequently, κ Aquarii itself is known as 虛梁三 (Xū Liáng sān, English: the Third Star of Temple.).[10] From this Chinese name, the name Heu Leang was appeared, meaning the Empty Bridge.[6]
Endymion, an 1818 poem by John Keats, describes the star in its form as a water urn thusly:
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"Crystalline brother of the belt of heaven,
Aquarius! to whom King Jove has given
Two liquid pulse streams 'stead of feather'd wings,
Two fan-like fountains, — thine illuminings.."[11]
USS Situla (AK-140) was a United States Navy Crater class cargo ship named after the star.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ 8.0 8.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) 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.
- ↑ LacusCurtius • Allen's Star Names — Aquarius
