GCIRS 7

GCIRS 7 is a pulsating red supergiant star located in the Galactic Center of the Milky Way galaxy. It is very luminous with a luminosity of 189,000 Sun’s. It is also one of the largest stars currently discovered in the galactic center with a size about 1,170 solar radii.^[4] If it was placed in the Solar System, its photosphere would engulf the orbit of Jupiter. The outer layers of the atmosphere is being blown away from stellar winds of the central cluster. This forms a cometary tail north of the star.^[7] It formed some 6.5 to 10 million years ago together with many of the massive stars in the galactic center.^[8]

GCIRS 7

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Sagittarius[1]
Right ascension	17h 45m 39.987s[2]
Declination	−29° 00′ 22.24″[2]
Characteristics
Evolutionary stage	Red supergiant
Spectral type	M1I[3]
Apparent magnitude (J)	14.197±0.137[2]
Apparent magnitude (H)	9.260±0.118[2]
Apparent magnitude (K)	6.503±0.017[2]
J−H color index	4.937[citation needed]
J−K color index	7.694[citation needed]
Details
Mass	20 – 25[4] M☉
Radius	1,170±60[4] R☉
Luminosity	189,000+42,000 −35,000[3] L☉
Surface gravity (log g)	−0.6[5] cgs
Temperature	3,600±195,[3] 3,400[6] K
Metallicity [Fe/H]	−0.02[5] dex
Age	6.5 – 10[3] Myr
Other designations
GCIRS 7, 2MASS J17454004-2900225[2]
Database references
SIMBAD	data

GCIRS 7 is important for observations of the galactic center.^[7]

See also

• KW Sagittarii, another red supergiant in Sagittarius
• VX Sagittarii, another red supergiant (or possible super-AGB star) in Sagittarius