Coordinates

RA: 21^h44^m41^s.152
DEC: +38^∘19'17''.061
Position-uncertainty [arcsec]: 1.829 × 10^-5
Galactic-longitude [deg]: 87.33
Galactic-latitude [deg]: -11.32
Coordinate-Reference

Binary System

Alternative Name: Cyg X-2
X-ray Type: XB, ZS, RP
Mean Distance [kpc]: 3.99^[1]
Distance Range [kpc]: 3.72 - 4.15^[1]
Hydrogen Column density [10²² cm⁻²]: 0.39
^[1]
G-band Absorption [mag]: 1.58
^[1]

Compact Object

Mass[M_☉]: 1.7100000381469727^[1]

Orbital Period [d]: 9.841666666666667^[1]


soft energy band: 0.3-10.0 keV
soft-band flux [10^-12 erg cm^-2 s^-1]:4459.37 - 16910.0
soft X-ray variability: 3.79

Optical Counterpart

Gaia DR3 Name: 1952859683185470208
Mass[M_☉]: 0.5799999833106995^[1]
Spectral Type: A9III^[1]
G [mag]: 14.702(0.007)
^[1]
V [mag]: 14.68(0.19)
^[1]
J [mag]: 13.396(0.031)
^[1]
H [mag]: 13.155(0.035)
^[1]
K [mag]: 13.049(0.034)
^[1]
W1 [mag]: 13.050(0.013)
^[1]
W2 [mag]: 12.902(0.011)
^[1]