Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cygnus |
Right ascension | 20h 14m 31.76669s [1] |
Declination | 36° 39′ 39.5982″ [1] |
Apparent magnitude (V) | 7.91 [2] (7.86 - 7.93 [3] ) |
Characteristics | |
Evolutionary stage | Wolf-Rayet |
Spectral type | WC7pd + O9V [4] |
U−B color index | −0.40 [2] |
B−V color index | +0.29 [2] |
Variable type | WR [5] |
Astrometry | |
Proper motion (μ) | RA: −2.681 [1] mas/yr Dec.: −5.739 [1] mas/yr |
Parallax (π) | 0.4898 ± 0.0172 mas [1] |
Distance | 6,700 ± 200 ly (2,040 ± 70 pc) |
Absolute magnitude (MV) | −5.7 [6] (−4.18 + −4.34) [4] |
Orbit [6] | |
Period (P) | 4,766 ± 66 |
Semi-major axis (a) | 16 AU |
Eccentricity (e) | 0.178 ± 0.042 |
Inclination (i) | 67° |
Semi-amplitude (K1) (primary) | 27.9 ± 1.2 km/s |
Semi-amplitude (K2) (secondary) | 6.1 ± 1.3 km/s |
Details | |
WR | |
Mass | 9.49±3.41 [7] M☉ |
Radius | 3.8 ± 1 [4] R☉ |
Luminosity | 398,000 [8] L☉ |
Temperature | 60,000 ± 5,000 [4] K |
O | |
Mass | 17.34±1.91 [7] M☉ |
Radius | 7.7 ± 1 [4] R☉ |
Luminosity | 158,000 [8] L☉ |
Surface gravity (log g) | 4.0 ± 0.3 [4] cgs |
Temperature | 32,000 ± 2,000 [4] K |
Rotational velocity (v sin i) | 220 ± 20 [4] km/s |
Age | 4.1 [8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
WR 137 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus.
WR 137, together with WR 134 and WR 135, was one of three stars in Cygnus observed in 1867 to have unusual spectra consisting of intense emission lines rather than the more normal continuum and absorption lines. These were the first members of the class of stars that came to be called Wolf-Rayet stars (WR stars) after Charles Wolf and Georges Rayet who discovered their unusual appearance. [9] It is a member of the carbon sequence of WR stars, indicated by the lack of nitrogen lines and the strength of carbon emission. WR 137 has a spectrum with CIII emission weaker than CIV and OV weaker still, leading to the assignment of a WC7 spectral type. The spectrum also shows emission lines of HeII and OIV. [10] [11]
WR 137 is a binary system, with an O9 main sequence or giant companion. The two stars orbit every thirteen years in a mildly eccentric orbit, and there is an episode of dust production near periastron. The inclination of the orbit is uncertain, most likely near 67° but with some analyses suggesting values around 23°. [6] The O star is visually brighter and more massive, but the WR star dominates the spectrum and has a higher bolometric luminosity. Visible in the spectrum are absorption lines and some narrow emission lines, each thought to originate from the secondary star. The line profiles suggest a decretion disc around the star, produced by its rapid rotation, which would make it the only known system containing a WR star and an Oe star. [8]
WR 137 is about a degree away from WR 135 and the two are believed to lie at approximately the same distance from Earth within the Cygnus OB3 association. [13] Its properties are uncertain because of the presence of the hot luminous companion. A pseudo-fit of the combined spectrum yielded a temperature of 56,000 K, a luminosity of 537,000 L☉, and a radius of 10 R☉. A more typical radius for a WC7 star would be 4.5 R☉, implying a hotter temperature. [6]
Evolutionary modelling of the WR 137 pair suggest an initial mass for the primary of 60 M☉ and for the secondary of 30 M☉, with an age of 4.1 million years. The initial orbital period would have been around 1,580 days. Around three M☉ have been transferred from the primary to the secondary. [8]
WR 136 is a Wolf–Rayet star located in the constellation Cygnus. It is in the center of the Crescent Nebula. Its age is estimated to be around 4.7 million years and it is nearing the end of its life. Within a few hundred thousand years, it is expected to explode as a supernova.
HD 5980 is a multiple star system on the outskirts of NGC 346 in the Small Magellanic Cloud (SMC) and is one of the brightest stars in the SMC.
WR 22, also known as V429 Carinae or HR 4188, is an eclipsing binary star system in the constellation Carina. The system contains a Wolf-Rayet (WR) star that is one of the most massive and most luminous stars known, and is also a bright X-ray source due to colliding winds with a less massive O class companion. Its eclipsing nature and apparent magnitude make it very useful for constraining the properties of luminous hydrogen-rich WR stars.
WR 46 is a Wolf-Rayet star in the constellation of the Southern Cross of apparent magnitude +10.8. It is located at 55 arcmin north of Theta2 Crucis. The star is a member of the distant stellar association Cru OB4, and is around 2,900 parsecs or 9,300 light years from the Solar System.
HD 38282 is a massive spectroscopic binary star in the Tarantula Nebula, consisting of two hydrogen-rich Wolf-Rayet stars.
WR 148 is a spectroscopic binary in the constellation Cygnus. The primary star is a Wolf–Rayet star and one of the most luminous stars known. The secondary has been suspected of being a stellar-mass black hole but may be a class O main sequence star.
Theta Muscae is a multiple star system in the southern constellation Musca, containing a Wolf-Rayet star and two massive companions. With an apparent magnitude of 5.5, it is the second-brightest Wolf–Rayet star in the sky, although much of the visual brightness comes from the massive companions and it is not one of the closest of its type.
WR 134 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus, surrounded by a faint bubble nebula blown by the intense radiation and fast wind from the star. It is five times the radius of the sun, but due to a temperature over 63,000 K it is 400,000 times as luminous as the Sun.
CD Crucis, also known as HD 311884, is an eclipsing binary star system in the constellation Crux. It is around 14,000 light years away near the faint open cluster Hogg 15. The binary contains a Wolf–Rayet star and is also known as WR 47.
AB8, also known as SMC WR8, is a binary star in the Small Magellanic Cloud (SMC). A Wolf-Rayet star and a main sequence companion of spectral type O orbit in a period of 16.638 days. It is one of only nine known WO stars, the only Wolf-Rayet star in the SMC not on the nitrogen sequence, and the only Wolf-Rayet star in the SMC outside the main bar.
WR 30a is a massive spectroscopic binary in the Milky Way galaxy, in the constellation Carina. The primary is an extremely rare star on the WO oxygen sequence and the secondary a massive class O star. It appears near the Carina Nebula but is much further away.
WR 135 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus, surrounded by a faint bubble nebula blown by the intense radiation and fast wind from the star. It is just over four times the radius of the sun, but due to a temperature of 63,000 K it is 250,000 times as luminous as the sun.
WR 111 is a Wolf-Rayet (WR) star in the constellation Sagittarius. It is magnitude 7.8 and lies about 5,150 light-years away. It is one of the brightest and most closely studied WR stars.
WR 86 is a visual binary in the constellation Scorpius consisting of a Wolf-Rayet star and a β Cephei variable. It lies 2° west of NGC 6357 on the edge of the Great Rift in the Milky Way in the tail of the Scorpion.
WR 3 is a Wolf-Rayet star located around 9,500 light years away from Earth in the constellation of Cassiopeia.
WR 12 is a spectroscopic binary in the constellation Vela. It is an eclipsing binary consisting of a Wolf-Rayet star and a luminous companion of unknown spectral type. The primary is one of the most luminous stars known.
WR 9 is a spectroscopic binary in the constellation Puppis consisting of a Wolf-Rayet star and a class O star. It is around 12,000 light years away.
HD 151932, also known as WR 78, is a Wolf-Rayet star located in the constellation Scorpius, close to the galactic plane. Its distance is around 1,300 parsecs away from the Earth. Despite being a blue-colored Wolf-Rayet star, it is extremely reddened by interstellar extinction, so its apparent magnitude is brighter for longer-wavelength passbands. HD 151932 lies about 22′ west of the open cluster NGC 6231, the center of the OB association Scorpius OB1; it is not clear whether it is a part of the association or not. With an apparent magnitude of about 6.5, it is one of the few Wolf-Rayet stars that can be seen with the naked eye.
WR 120 is a binary containing two Wolf-Rayet stars in the constellation of Scutum, around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33. From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.
CV Serpentis is a binary star system in the equatorial constellation of Serpens. It is a detached eclipsing binary with an orbital period of 29.7 days. The system includes a Wolf–Rayet (WR) star with the identifier WR 113. The system is located at a distance of approximately 6,700 light years from the Sun based on parallax measurements. It is a member of the Serpens OB2 association of co-moving stars.