Mu Aquarii

Mu Aquarii
Location of μ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 20h 52m 39.23277s[1]
Declination −08° 58′ 59.9499″[1]
Apparent magnitude (V) 4.731[2]
Characteristics
Spectral type A3m[3]
U−B color index +0.149[2]
B−V color index +0.322[2]
Astrometry
Radial velocity (Rv)−9.1[4] km/s
Proper motion (μ) RA: +45.75[1] mas/yr
Dec.: -33.59[1] mas/yr
Parallax (π)20.74 ± 0.29 mas[1]
Distance157 ± 2 ly
(48.2 ± 0.7 pc)
Absolute magnitude (MV)+1.31[5]
Orbit[6]
Period (P)1,566±3 d
Semi-major axis (a)≥ 67.06 Gm (0.4483 AU)
Eccentricity (e)0.23±0.19
Periastron epoch (T)2,410,497±52 JD
Semi-amplitude (K1)
(primary)		3.2±0.6 km/s
Details
A
Radius3.54+0.45
−0.15[7] R☉
Luminosity25.6±1.4[8] L☉
Surface gravity (log g)3.99[8] cgs
Temperature6,906+151
−405[8] K
Rotational velocity (v sin i)53.7[8] km/s
Other designations
μ Aqr, 6Aquarii, BD−09 5598, FK5 1547, HD 198743, HIP 103045, HR 7990, SAO 144895, WDS 20527-0859A[9]
Database references
SIMBADdata

Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star[10] system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7.[2] Based upon parallax measurements, the distance to this system is about 157 light-years (48 parsecs).[1] It is drifting closer to the Sun with a radial velocity of −9.1 km/s.[4]

This star was tentatively identified as a single-lined spectroscopic binary by Helmut A. Abt in 1961.[11] It has an orbital period of 4.29 yr and an eccentricity (ovalness) of 0.23.[6] The pair have been resolved by speckle interferometry, showing an angular separation of 0.06″.[12] The visible spectrum matches a stellar classification of A3m, with the 'm' suffix indicating that this is an Am, or chemically peculiar star.[3] The primary has an estimated 3.5 times the Sun's radius and is radiating 26 times the luminosity of the Sun from its photosphere at an effective temperature of 6,906 km/s.[7]

This star together with ν Aquarii is Albulaan /ˌælbjəˈlɑːn/, derived from an Arabic term al-bulaʽān (ألبولعان) meaning "the two swallowers". This star, along with ε Aqr (Albali) and ν Aqr (Albulaan), were al Bulaʽ (البلع), the Swallower.[13][14] In Chinese, 女宿 (Nǚ Xiù), meaning Girl (asterism) (or Woman), refers to an asterism consisting of μ Aquarii, ε Aquarii, 4 Aquarii, 5 Aquarii and 3 Aquarii.[15] Consequently, the Chinese name for μ Aquarii itself is 女宿二 (Nǚ Xiù èr, English: the Second Star of Girl / Woman.)[16]

  1. ^ a b c d e f Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference sps1966 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference aj74_375 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcsrv was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Abt_levy_1985 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference aaa493_3_1099 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference mnras389_2_869 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Abt1961 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Hartkopf_et_al_2000 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference davis_jr1944 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference allen1963 was invoked but never defined (see the help page).
  15. ^ (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.
  16. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 14 日