Cygnus X-3

Cygnus X-3
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Cygnus
Right ascension	20h 32m 25.78s
Declination	+40° 57′ 27.9″
Characteristics
Spectral type	WN 4–6
Apparent magnitude (H)	13.192
Apparent magnitude (J)	15.309
Apparent magnitude (K)	11.921
Astrometry
Radial velocity (Rv)	208+113; −127 km/s
Distance	7,400±1,100 pc
Absolute magnitude (MV)	−4.5
Orbit
Period (P)	4.8 hours
Semi-amplitude (K1); (primary)	379+124; −149 km/s
Details
WR
Mass	8–14 M☉
Radius	<2 R☉
Luminosity	209,000+93,000; −64,000 L☉
Temperature	more than 80,000 K
compact object
Mass	2.4+2.1; −1.1 M☉
Other designations
	V1521 Cyg, 18P 57, WR 145a, X Cyg X-3, RX J2032.3+4057, INTEGRAL1 118, 2U 2030+40, 3U 2030+40, 4U 2030+40.
Database references
SIMBAD	data

Cygnus X-3 is a high-mass X-ray binary (HMXB), one of the stronger binary X-ray sources in the sky. It is often considered to be a microquasar, and it is believed to be a compact object in a binary system which is pulling in a stream of gas from an ordinary star companion. It is one of only two known HMXBs containing a Wolf–Rayet star. It is invisible visually, but can be observed at radio, infrared, X-ray, and gamma-ray wavelengths.

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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Cygnus
Right ascension	20^h 32^m 25.78^s^[1]
Declination	+40° 57′ 27.9″^[1]
Characteristics
Spectral type	WN 4–6^[2]
Apparent magnitude (H)	13.192^[3]
Apparent magnitude (J)	15.309^[3]
Apparent magnitude (K)	11.921^[3]
Astrometry

Radial velocity (R_v)	208+113 −127^[2] km/s
Distance	7,400±1,100^[4] pc
Absolute magnitude (M_V)	−4.5^[2]

Orbit^[2]
Period (P)	4.8 hours
Semi-amplitude (K₁) (primary)	379+124 −149 km/s
Details
WR
Mass	8–14^[2] `M`_☉
Radius	<2^[2] `R`_☉
Luminosity	209,000+93,000 −64,000^[2] `L`_☉
Temperature	more than 80,000^[2] K
compact object
Mass	2.4+2.1 −1.1^[5] `M`_☉
Other designations
V1521 Cyg, 18P 57, WR 145a, X Cyg X-3, RX J2032.3+4057, INTEGRAL1 118, 2U 2030+40, 3U 2030+40, 4U 2030+40.^[3]
Database references
SIMBAD	data