Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Grus |
Right ascension | 21h 53m 55.72620s [1] |
Declination | –37° 21′ 53.4790″ [1] |
Apparent magnitude (V) | 3.003 [2] |
Characteristics | |
Spectral type | B8 III [3] or B8IV-Vs [4] |
U−B color index | –0.307 [2] |
B−V color index | –0.121 [2] |
Astrometry | |
Radial velocity (Rv) | –2.1 [5] km/s |
Proper motion (μ) |
RA: +98.07
[1]
mas/
yr Dec.: –13.22 [1] mas/ yr |
Parallax (π) | 15.45 ± 0.67 mas [1] |
Distance | 211 ± 9
ly (65 ± 3 pc) |
Absolute magnitude (MV) | −1.05 [6] |
Details | |
Mass | 3.06 [7] M☉ |
Radius | 4.5 [8] R☉ |
Luminosity | 373 [6] L☉ |
Surface gravity (log g) | 3.79 [7] cgs |
Temperature | 12,520 [9] K |
Rotation | 4.987 [10] d |
Rotational velocity (v sin i) | 57 [11] km/s |
Age | 75 [7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Gamma Gruis or γ Gruis, formally named Aldhanab ( /ˈældənæb/), [13] is a star in the southern constellation of Grus (it once belonged to the Ptolemaic constellation Piscis Austrinus). With an apparent visual magnitude of 3.0, [2] it is the third-brightest star in Grus. Based upon parallax measurements, this star is located at a distance of roughly 211 light-years (65 parsecs) from the Sun. [1]
γ Gruis ( Latinised to Gamma Gruis) is the system's Bayer designation.
It bore the traditional Arabic name Al Dhanab, from the Arabic الذنب al-dhanab "the tail" (of the Southern Fish) [14]when it was still part of Piscis Austrinus with the Bayer designation κ Piscis Austrini (Kappa Piscis Austrini). In 2016, the IAU organized a Working Group on Star Names (WGSN) [15] to catalog and standardize proper names for stars. The WGSN approved the name Aldhanab for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. [13]
In Chinese, 敗臼 (Bài Jiù), meaning Decayed Mortar, refers to an asterism consisting of Gamma Gruis, Lambda Gruis, Gamma Piscis Austrini and 19 Piscis Austrini. [16] Consequently, the Chinese name for Gamma Gruis itself is 敗臼一 (Bài Jiù yī, English: the First Star of Decayed Mortar.) [17]
Analysis of the spectrum by N. Houk in 1979 shows it to match a stellar classification of B8 III, [3] with the luminosity class of III indicating this is a giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence. R. O. Gray and R. F. Garrison in 1989 found a less evolved class of B8IV-Vs. [4] The luminosity of Gamma Gruis is around 390 times that of the Sun, with a significant portion of the energy emission being in the ultraviolet. [18] Its outer envelope has an effective temperature of 12,520 K, [9] which gives the star a blue-white hue. Gamma Gruis is rotating relatively rapidly with a projected rotational velocity of 57 km s−1. [11] By way of comparison, the Sun has an azimuthal velocity along its equator of just 2 km s−1.
Based upon analysis of data collected during the Hipparcos mission, this star may have a proper motion companion that is causing gravitational perturbation of Gamma Gruis. [19]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Grus |
Right ascension | 21h 53m 55.72620s [1] |
Declination | –37° 21′ 53.4790″ [1] |
Apparent magnitude (V) | 3.003 [2] |
Characteristics | |
Spectral type | B8 III [3] or B8IV-Vs [4] |
U−B color index | –0.307 [2] |
B−V color index | –0.121 [2] |
Astrometry | |
Radial velocity (Rv) | –2.1 [5] km/s |
Proper motion (μ) |
RA: +98.07
[1]
mas/
yr Dec.: –13.22 [1] mas/ yr |
Parallax (π) | 15.45 ± 0.67 mas [1] |
Distance | 211 ± 9
ly (65 ± 3 pc) |
Absolute magnitude (MV) | −1.05 [6] |
Details | |
Mass | 3.06 [7] M☉ |
Radius | 4.5 [8] R☉ |
Luminosity | 373 [6] L☉ |
Surface gravity (log g) | 3.79 [7] cgs |
Temperature | 12,520 [9] K |
Rotation | 4.987 [10] d |
Rotational velocity (v sin i) | 57 [11] km/s |
Age | 75 [7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Gamma Gruis or γ Gruis, formally named Aldhanab ( /ˈældənæb/), [13] is a star in the southern constellation of Grus (it once belonged to the Ptolemaic constellation Piscis Austrinus). With an apparent visual magnitude of 3.0, [2] it is the third-brightest star in Grus. Based upon parallax measurements, this star is located at a distance of roughly 211 light-years (65 parsecs) from the Sun. [1]
γ Gruis ( Latinised to Gamma Gruis) is the system's Bayer designation.
It bore the traditional Arabic name Al Dhanab, from the Arabic الذنب al-dhanab "the tail" (of the Southern Fish) [14]when it was still part of Piscis Austrinus with the Bayer designation κ Piscis Austrini (Kappa Piscis Austrini). In 2016, the IAU organized a Working Group on Star Names (WGSN) [15] to catalog and standardize proper names for stars. The WGSN approved the name Aldhanab for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. [13]
In Chinese, 敗臼 (Bài Jiù), meaning Decayed Mortar, refers to an asterism consisting of Gamma Gruis, Lambda Gruis, Gamma Piscis Austrini and 19 Piscis Austrini. [16] Consequently, the Chinese name for Gamma Gruis itself is 敗臼一 (Bài Jiù yī, English: the First Star of Decayed Mortar.) [17]
Analysis of the spectrum by N. Houk in 1979 shows it to match a stellar classification of B8 III, [3] with the luminosity class of III indicating this is a giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence. R. O. Gray and R. F. Garrison in 1989 found a less evolved class of B8IV-Vs. [4] The luminosity of Gamma Gruis is around 390 times that of the Sun, with a significant portion of the energy emission being in the ultraviolet. [18] Its outer envelope has an effective temperature of 12,520 K, [9] which gives the star a blue-white hue. Gamma Gruis is rotating relatively rapidly with a projected rotational velocity of 57 km s−1. [11] By way of comparison, the Sun has an azimuthal velocity along its equator of just 2 km s−1.
Based upon analysis of data collected during the Hipparcos mission, this star may have a proper motion companion that is causing gravitational perturbation of Gamma Gruis. [19]