Gamma2 Sagittarii

For other stars with this Bayer designation, see γ Sagittarii.
γ2 Sagittarii
Location of γ2 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sagittarius
Right ascension 18h 05m 48.484s[1]
Declination 30° 25′ 26.50″[1]
Apparent magnitude (V) +2.96[2]
Characteristics
Evolutionary stage K-type giant
Spectral type K0III[2]
U−B color index +0.77[3]
B−V color index +1.006[2]
Astrometry
Radial velocity (Rv)22.0[4] km/s
Proper motion (μ) RA: −48.839 mas/yr[1]
Dec.: −204.86 mas/yr[1]
Parallax (π)30.6791 ± 0.4451 mas[2]
Distance106.2+1.6
−1.5 ly
(32.58+0.48
−0.47 pc)[2]
Absolute magnitude (MV)+0.395[2]
Details[2]
Mass1.98±0.22 M☉
Radius12.07±0.27 R☉
Luminosity73.45±2.42 L☉
Surface gravity (log g)2.712±0.092 cgs
Temperature4,864±36 K
Metallicity [Fe/H]−0.153±0.028 dex
Other designations
Alnasl, Nushaba,[5] Awal al Warida, γ Sagittarii, γ Sgr, Gamma2 Sgr, 10 Sagittarii, CPD−30 5241, FK5 679, GC 24632, HD 165135, HIP 88635, HR 6746, PPM 297231, SAO 209696[6]
Database references
SIMBADdata

Gamma2 Sagittarii (γ2 Sagittarii, abbreviated Gamma2 Sgr, γ2 Sgr), formally named Alnasl /ælˈnæzəl/,[7] is a 3rd-magnitude star in the zodiac constellation of Sagittarius. The location of this star is in the handle of the Bow of Sagittarius the Centaur. It is approximately 32.6 parsecs (106 light-years) from the Sun and has an apparent visual magnitude of +2.96,[2] making it the seventh-brightest star in the constellation.

It forms part of a double star along with a fainter optical companion designated Gamma1 Sagittarii located about 50 arcminutes north of this star. The latter is a magnitude 4.7 Cepheid variable star that also has the variable star designation W Sagittarii.[8][9]

  1. ^ a b c Cite error: The named reference DR3 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h Cite error: The named reference otonni was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference scfs was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference olcott1907 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. ^ Naming Stars, IAU.org, retrieved 16 December 2017
  8. ^ Cite error: The named reference kaler was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference burnham1978 was invoked but never defined (see the help page).