Mu1 Gruis

For other stars with this Bayer designation, see μ Gruis.
Mu1 Gruis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Grus
Right ascension 22h 15m 36.93338s[1]
Declination −41° 20′ 48.3558″[1]
Apparent magnitude (V) 4.79[2] (5.20 + 6.68)[3]
Characteristics
Spectral type G8 III + G[4]
U−B color index +0.47[2]
B−V color index +0.80[2]
Astrometry
Radial velocity (Rv)−4.82±1.54[1] km/s
Proper motion (μ) RA: +30.774[1] mas/yr
Dec.: +42.645[1] mas/yr
Parallax (π)13.5115 ± 0.2846 mas[1]
Distance241 ± 5 ly
(74 ± 2 pc)
Absolute magnitude (MV)+0.17[5]
Orbit[6]
Period (P)19.04+0.16
−0.18 yr
Semi-major axis (a)0.168+0.003
−0.002″
Eccentricity (e)0.561+0.025
−0.020
Inclination (i)65.69+0.44
−0.53°
Longitude of the node (Ω)104.2+1.6
−1.8°
Periastron epoch (T)1996.35+0.17
−0.18
Argument of periastron (ω)
(secondary)		92.61+0.67
−0.54°
Details
A
Radius9.3+1.4
−1.3[1] R☉
Luminosity66.9+1.8
−1.6[1] L☉
Temperature5,422+423
−377[1] K
Other designations
μ1 Gru, CD−41° 14810, FK5 3777, HD 211088, HIP 109908, HR 8486, SAO 231055, WDS J22156-4121[7]
Database references
SIMBADdata

Mu1 Gruis, Latinized from μ1 Gruis, is a binary star[3] system in the southern constellation of Grus. It is visible to the naked eye with a combined apparent visual magnitude of 4.79.[2] The distance to this system, as determined using an annual parallax shift of 11.44 mas as seen from the Earth,[8] is around 275 light years. It is drifting closer with a heliocentric radial velocity of −5 km/s.[1]

The pair orbit each other with a period of 19 years and an eccentricity of 0.56.[6] The yellow-hued primary component is an evolved giant star with stellar classification of G III[4] and visual magnitude 5.20.[3] With the supply of hydrogen at its core exhausted, it cooled and expanded; at present it has nine[1] times the girth of the Sun. The star is radiating 67 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,422 K.[1]

The secondary component is magnitude 6.68 and classed as a G-type star,[3] although its color index and absolute magnitude suggest it is of type A6.[6]

  1. ^ a b c d e f g h i j k l Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1978 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 c Cite error: The named reference Mendez2017 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).