12 Aquilae

This article is about i Aquilae. Not to be confused with ι Aquilae or l Aquilae.
12 Aquilae
Location of 12 Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 01m 40.82707s[1]
Declination –05° 44′ 20.8134″[1]
Apparent magnitude (V) 4.02[2]
Characteristics
Spectral type K1 III[3]
U−B color index +1.04[2]
B−V color index +1.104[4]
R−I color index 0.54
Astrometry
Radial velocity (Rv)–43.92 ± 0.18[4] km/s
Proper motion (μ) RA: –24.41[1] mas/yr
Dec.: –39.66[1] mas/yr
Parallax (π)22.66 ± 0.23 mas[1]
Distance144 ± 1 ly
(44.1 ± 0.4 pc)
Absolute magnitude (MV)0.726[5]
Details
Radius12[4] R☉
Luminosity60[4] L☉
Surface gravity (log g)2.6[4] cgs
Temperature4,603[4] K
Metallicity [Fe/H]–0.19[5] dex
Rotational velocity (v sin i)3.6[4] km/s
Age4.64 ± 2.35[5] Gyr
Other designations
i Aquilae, BD–05 4840, HD 176678, HIP 93429, HR 7193, SAO 142931.[6]
Database references
SIMBADdata

12 Aquilae (abbreviated 12 Aql) is a star in the equatorial constellation of Aquila. 12 Aquilae has the Bayer designation of i Aquilae and is most easily recognized in the sky being next to the brighter star λ (lambda) Aquilae.

In Chinese, 天弁 (Tiān Biàn), meaning Market Officer, refers to an asterism consisting of 12 Aquilae, α Scuti, δ Scuti, ε Scuti, β Scuti, η Scuti, λ Aquilae, 15 Aquilae and 14 Aquilae.[7] Consequently, 12 Aquilae itself is known as 天弁六 (Tiān Biàn liù, English: the Sixth Star of Market Officer.)

This star has an apparent visual magnitude of 4.02,[2] which is bright enough to be seen with the naked eye, although, according to the Bortle Dark-Sky Scale, it is a challenge to view from the inner city. Based upon an annual parallax shift of 22.66 mas, the distance to this star is 144 light-years (44 parsecs) with a margin of error of one light-year. This is an evolved giant star of stellar class K1 III.[3] It has 12[4] times the radius of the Sun and shines with 60[4] times the Sun's luminosity. This energy is being radiated from its outer atmosphere at an effective temperature of 4,603 K,[4] giving it the cool orange hue of a K-type star.[8]

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference apj116 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i j Cite error: The named reference aj135_1_209 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference aaa480_1_91 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ (in 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.
  8. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).