Pismis 24-1
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Pismis 24-1, also known as HD 319718, is the brightest star of the open cluster Pismis 24 within the nebula NGC 6357 about 6,500 light-years away. It was once thought to be the most massive star known, but is composed of at least three individual objects, each still among the most luminous and most massive stars known.
Quick Facts Observation data Epoch J2000 Equinox J2000, Apparent magnitude (V) ...
Pismis 24-1 is the brightest point of light at the centre of this optical image of the NGC 6357 region. Credit: ESO/IDA/Danish 1.5 m/ R. Gendler, U.G. Jørgensen, J. Skottfelt, K. Harpsøe | |
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Scorpius |
NE | |
Right ascension | 17h 24m 43.497s[1] |
Declination | –34° 11′ 56.86″[1] |
Apparent magnitude (V) | 11.00[2] |
SW | |
Right ascension | 17h 24m 43.481s[1] |
Declination | –34° 11′ 57.21″[1] |
Apparent magnitude (V) | 11.10[2] |
Characteristics | |
NE | |
Spectral type | O3.5If*[3] |
Variable type | eclipsing[4] |
SW | |
Spectral type | O4III(f+)[3] |
Astrometry | |
Radial velocity (Rv) | −2.0[5] km/s |
Proper motion (μ) | RA: −0.1[6] mas/yr Dec.: −1.3[6] mas/yr |
Distance | 6,500[7] ly (2,000[7] pc) |
Absolute magnitude (MV) | −7.50[3] |
NE | |
Absolute magnitude (MV) | −6.41[4] |
SW | |
Absolute magnitude (MV) | −6.28[4] |
Details | |
NE | |
Mass | 74[1] M☉ |
Radius | 18 R☉ |
Luminosity | 776,000[1] L☉ |
Temperature | 42,500/41,500[4] K |
SW | |
Mass | 66[1] M☉ |
Radius | 17 R☉ |
Luminosity | 646,000[1] L☉ |
Temperature | ~40,000[1] K |
Other designations | |
NE: Pismis 24-1NE, HD 319718A | |
SW: Pismis 24-1SW, HD 319718B | |
Database references | |
SIMBAD | data |
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