Coordinates

RA: 21^h39^m30^s.685
DEC: +56^∘59'10''.387
Position-uncertainty [arcsec]: 1.655 × 10^-5
Galactic-longitude [deg]: 99.01
Galactic-latitude [deg]: 3.31
Coordinate-Reference

Binary System

Alternative Name: Ginga 2138+56
X-ray Type: BE,CL,HT,XP,XT
Mean Distance [kpc]: 7.35
Distance Range [kpc]: 6.63 - 8.02
Hydrogen Column density [10²¹ cm⁻²]: 7.12

Compact Object

Orbital Period [d]: 20.85^[1]
Pulse Period [s]: 65.35^[1][2]
CRSF energy [keV]: 30,28,45,30,55^{[1][2][3][4][5][6]}
Chandra flux [10^-12 erg cm^-2 s^-1]:0.66 (0.5-7.0 keV)
Swift/XRT flux [10^-12 erg cm^-2 s^-1]:470.1 (0.3-10.0 keV)

Optical Counterpart

Gaia DR3 Name: 2178178409188167296
Counterpart: confirmed
Spectral Type: B1-B2Ve^[1]
G [mag]: 13.8162(0.0030)
J [mag]: 11.829(0.024)
H [mag]: 11.414(0.028)
K [mag]: 10.926(0.020)
W1 [mag]: 10.290(0.010)
W2 [mag]: 10.002(0.007)

Comments

Possible range of orbital periods: 23 - 147.3 d