HD 15558
Star in the constellation Cassiopeia / From Wikipedia, the free encyclopedia
HD 15558 (HIP 11832) is a massive O-type multiple star system in Cassiopeia and is specifically in our galaxy's Heart Nebula in the open cluster IC 1805. The primary is a very massive star with 152 M☉ and 660,000 L☉.
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000.0 Equinox J2000.0 | |
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Constellation | Cassiopeia |
Right ascension | 02h 32m 42.537s[1] |
Declination | 61° 27′ 21.57″[1] |
Apparent magnitude (V) | 7.87[2] |
Characteristics | |
Spectral type | O4.5III(f)[3] (O5.5III(f) + O7V[4]) |
U−B color index | −0.55[2] |
B−V color index | +0.43[2] |
V−R color index | +0.38[2] |
R−I color index | +0.40[2] |
J−H color index | +0.18[2] |
Astrometry | |
Radial velocity (Rv) | −45.10±1.50[5] km/s |
Proper motion (μ) | RA: −0.478[1] mas/yr Dec.: −0.849[1] mas/yr |
Parallax (π) | 0.5764 ± 0.0662 mas[1] |
Distance | approx. 5,700 ly (approx. 1,700 pc) |
Orbit | |
Period (P) | 442 days[4] (1.2 [4] yr) |
Semi-major axis (a) | 726 R☉[4] |
Eccentricity (e) | 0.37±0.07[4] |
Argument of periastron (ω) (secondary) | 120[4]° |
Details | |
Mass | >152±51[4] M☉ |
Radius | 16.4[6] R☉ |
Luminosity | ~660,000[4] L☉ |
Surface gravity (log g) | 3.7[6] cgs |
Temperature | 39,500[6] K |
Age | 0.7-3[4][7] Myr |
secondary | |
Mass | 46±11[4] M☉ |
Radius | 5.6[6] R☉ |
Other designations | |
Database references | |
SIMBAD | data |
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