An H-alpha image of the Heart Nebula. HD 15558 is located at the centre of the cluster, circled. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 02 32 42.537 |
| Declination | 61° 27′ 21.57″ |
| Apparent magnitude (V) | 7.87 |
| Characteristics | |
| Spectral type | O4.5III(f) (O5.5III(f) + O7V) |
| U−B color index | −0.55 |
| B−V color index | +0.43 |
| V−R color index | +0.38 |
| R−I color index | +0.40 |
| J−H color index | +0.18 |
| Astrometry | |
| Radial velocity (Rv) | −45.10±1.50 km/s |
| Proper motion (μ) | RA: −0.478 mas/yr Dec.: −0.849 mas/yr |
| Parallax (π) | 0.5764 ± 0.0662 mas |
| Distance | approx. 5,700 ly (approx. 1,700 pc) |
| Orbit | |
| Period (P) | 442 days (1.2 yr) |
| Semi-major axis (a) | 726 R☉ |
| Eccentricity (e) | 0.37±0.07 |
| Argument of periastron (ω) (secondary) | 120° |
| Details | |
| Mass | >152±51 M☉ |
| Radius | 16.4 R☉ |
| Luminosity | ~660,000 L☉ |
| Surface gravity (log g) | 3.7 cgs |
| Temperature | 39,500 K |
| Age | 0.7-3 Myr |
| secondary | |
| Mass | 46±11 M☉ |
| Radius | 5.6 R☉ |
| Other designations | |
| HD 15558, HIP 11832, SAO 12326, IDS 02251+6101, TYC 4046-44-1, UBV 2530, GCRV 1424, 2MASS J02324253+6127215, WDS J02327+6127, PPM 13720, BD+60°502, GSC 04046-00044, CCDM J02327+6127, IC 1805 148 | |
| Database references | |
| SIMBAD | data |
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☉.
Physical characteristics
HD 15558 A is a spectroscopic binary system containing at least two massive luminous class O stars. The primary is an O4.5 giant star with a surface temperature over 46,800 K. It has a mass of 152 M☉ and a luminosity of 660,000 L☉, making it one of the most massive stars in the Milky Way Galaxy. The star loses 1.5×10 M☉ per year. The secondary is an O7V star. It has a mass of 46 M☉. The primary may itself be a double star, suggested by the improbably large mass found from the binary orbit when compared to the other stellar parameters.
The Washington Double Star Catalog lists 11 companions within one arc minute of HD 15558 A, all fainter than 10th magnitude. In addition, it lists component E just over one arc minute away; it is another hot massive star, the 9th magnitude BD+60°501 with a spectral type of O7 V(n)((f))z.
See also
References
- ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
- ^ Sota, A.; Mainz Apellantiz, J.; Morrell, N.L; Barba, R.H; Walborn, N.R; et al. (2014). "The Galactic O-star spectroscopic survey (GOSSS). II. Bright southern stars". The Astrophysical Journal Supplement. 211 (1): 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
- ^ De Becker, M.; Rauw, G.; Manfroid, J.; Eenens, P. (2006). "Early-type stars in the young open cluster IC 1805. II. The probably single stars HD 15570 and HD 15629, and the massive binary/triple system HD 15558". Astronomy & Astrophysics. 456 (3): 1121. arXiv:astro-ph/0606379. Bibcode:2006A&A...456.1121D. doi:10.1051/0004-6361:20065300. S2CID 16519684.
- Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy & Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088.
- ^ Hillwig, T. C.; Gies, D. R.; Huang, W.; McSwain, M. V.; Wingert, D. W. (2006). "Binary and Multiple O-Type Stars in the Cassiopeia OB6 Association". The Astrophysical Journal. 639 (2): 1069–1080. arXiv:astro-ph/0512407. Bibcode:2006ApJ...639.1069H. doi:10.1086/499771. S2CID 119451956.
- ^ Garmany, C. D.; Massey, P. (1981). "HD 15558 - an extremely luminous O-type binary star". Publications of the Astronomical Society of the Pacific. 93: 500. Bibcode:1981PASP...93..500G. doi:10.1086/130866. S2CID 121457874.
- Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
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