Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cepheus |
Right ascension | 23h 00m 10.13337s [1] |
Declination | +60° 55′ 38.4168″ [1] |
Apparent magnitude (V) | 11.01 [2] |
Characteristics | |
Spectral type | WN8h [3] |
B−V color index | +1.17 [2] |
Astrometry | |
Proper motion (μ) |
RA: −2.595±0.040
[4]
mas/
yr Dec.: −1.691±0.042 [4] mas/ yr |
Parallax (π) | 0.2749 ± 0.0125 mas [5] |
Distance | 11,900 ± 500
ly (3,600 ± 200 pc) |
Absolute magnitude (MV) | −7.00 [6] |
Details | |
Mass | 32 [6] M☉ |
Radius | 20.81 [6] R☉ |
Luminosity | 1,023,000 [6] L☉ |
Temperature | 39,800 [6] K |
Other designations | |
Database references | |
SIMBAD | data |
WR 156 is a young massive and luminous Wolf–Rayet star in the constellation of Cepheus. Although it shows a WR spectrum, it is thought to be a young star still fusing hydrogen in its core.
WR 156 has a Hipparcos parallax of 3.16" indicating a distance of about a thousand light years, although with a fairly large margin of error. Other studies indicate that it is much more distant based on a very high luminosity and faint apparent magnitude. [6] The Gaia DR1 parallax is 0.07". The margin of error is larger than the measured parallax, but still the indication is for a very large distance. [7] In Gaia Data Release 2, the parallax is given as 0.2090±0.0251 mas but with a marker that the result may be unreliable. [4] In the Gaia Early Release 3, the solution was adjusted to 0.2749±0.0125 mas, still with significant astrometric noise excess. [5]
WR 156 has a WR spectrum on the nitrogen sequence, indicating strong emission of helium and nitrogen, but it also shows features of hydrogen. Therefore, it is given a spectral type of WN8h. Its outer layers are calculated to contain 30% hydrogen, one of the highest levels for any galactic Wolf Rayet star. [8]
WR 156 has a low temperature and slow stellar wind by Wolf Rayet standards, only 39,800 K and 660 km/s respectively. The wind is very dense, with total mass loss of more than 1/100,000 M☉/year. [6]
WR 156 is a young hydrogen-rich star, still burning hydrogen in its core but sufficiently luminous to have convected up nitrogen and helium fusion products to its surface. It shows 27% hydrogen at its surface. [6] It is estimated to have had an initial mass of 50 M☉ several million years ago. [8]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cepheus |
Right ascension | 23h 00m 10.13337s [1] |
Declination | +60° 55′ 38.4168″ [1] |
Apparent magnitude (V) | 11.01 [2] |
Characteristics | |
Spectral type | WN8h [3] |
B−V color index | +1.17 [2] |
Astrometry | |
Proper motion (μ) |
RA: −2.595±0.040
[4]
mas/
yr Dec.: −1.691±0.042 [4] mas/ yr |
Parallax (π) | 0.2749 ± 0.0125 mas [5] |
Distance | 11,900 ± 500
ly (3,600 ± 200 pc) |
Absolute magnitude (MV) | −7.00 [6] |
Details | |
Mass | 32 [6] M☉ |
Radius | 20.81 [6] R☉ |
Luminosity | 1,023,000 [6] L☉ |
Temperature | 39,800 [6] K |
Other designations | |
Database references | |
SIMBAD | data |
WR 156 is a young massive and luminous Wolf–Rayet star in the constellation of Cepheus. Although it shows a WR spectrum, it is thought to be a young star still fusing hydrogen in its core.
WR 156 has a Hipparcos parallax of 3.16" indicating a distance of about a thousand light years, although with a fairly large margin of error. Other studies indicate that it is much more distant based on a very high luminosity and faint apparent magnitude. [6] The Gaia DR1 parallax is 0.07". The margin of error is larger than the measured parallax, but still the indication is for a very large distance. [7] In Gaia Data Release 2, the parallax is given as 0.2090±0.0251 mas but with a marker that the result may be unreliable. [4] In the Gaia Early Release 3, the solution was adjusted to 0.2749±0.0125 mas, still with significant astrometric noise excess. [5]
WR 156 has a WR spectrum on the nitrogen sequence, indicating strong emission of helium and nitrogen, but it also shows features of hydrogen. Therefore, it is given a spectral type of WN8h. Its outer layers are calculated to contain 30% hydrogen, one of the highest levels for any galactic Wolf Rayet star. [8]
WR 156 has a low temperature and slow stellar wind by Wolf Rayet standards, only 39,800 K and 660 km/s respectively. The wind is very dense, with total mass loss of more than 1/100,000 M☉/year. [6]
WR 156 is a young hydrogen-rich star, still burning hydrogen in its core but sufficiently luminous to have convected up nitrogen and helium fusion products to its surface. It shows 27% hydrogen at its surface. [6] It is estimated to have had an initial mass of 50 M☉ several million years ago. [8]