NGC 3603-C

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NGC 3603-C
NGC3603 core.jpg
C is the brightest star to the left of the very close A (three not quite resolved stars at the very centre of the image) and B pair at the centre in this HST image of the central region of HD 97950.
Credit: NASA, ESA and Wolfgang Brandner (MPIA), Boyke Rochau (MPIA) and Andrea Stolte (University of Cologne)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Carina
Right ascension 11h 15m 07.589s [1]
Declination −61° 15′ 38.00″ [1]
Apparent magnitude  (V)11.89 [1]
Characteristics
Spectral type WN6h+? [2]
B−V color index 1.05 [1]
Astrometry
Proper motion (μ)RA: 2.4 [3]   mas/yr
Dec.: 2.8 [3]   mas/yr
Distance 7,600 [2]   pc
Absolute magnitude  (MV)−7.17 [2]
Orbit [4]
PrimaryC
Period (P)8.89 ± 0.01 days
Eccentricity (e)0.30 ± 0.04
Inclination (i)71°
Periastron epoch (T)2453546.61 ± 0.18
Argument of periastron (ω)
(secondary)		281 ± 7°
Semi-amplitude (K1)
(primary)		200 ± 23 km/s
Details
Mass 113 [2]   M☉
Radius 26.2 [2]   R☉
Luminosity 2,200,000 [2]   L☉
Temperature 44,000 [2]   K
Age 1.5 [2]   Myr
Other designations
NGC 3603-C, CD-60°3452C, CPD-60°2732C, HD  97950C, HIP  54948C, WR  43c, AAVSO  1110-60, NGC 3603 MDS 18
Database references
SIMBAD data

NGC 3603-C (HD 97950C) is a single-lined spectroscopic binary star system located at the centre of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. The primary has spectral type WN6h and is among the most luminous and most massive known.

Contents

HD 97950 was catalogued as a star, but was known to be a dense cluster or close multiple star. In 1926, the six brightest members were given letters from A to F, [5] although several of them have since been resolved into more than one star. [6] Star C was shown to be a binary, but its companion has not been observed. [4]

HD 97950C is a Wolf-Rayet (WR) star, with spectra dominated by strong broadened emission lines. Type WN6 indicates that ionised nitrogen lines are strong in comparison to ionised carbon lines, and the suffix h indicates that hydrogen is also seen in the spectrum. This type of WR star is not the classical stripped helium-burning aged star, but a young highly luminous object with CNO cycle fusion products showing at the surface due to strong conventional and rotational mixing, and high mass loss rates from the atmosphere. The emission lines are generated in the stellar wind and the photosphere is completely hidden. The surface fraction of hydrogen is still estimated to be 70%. [2]

The two component stars of NGC 3603-C circle each other every nine days. It is assumed that the secondary is sufficiently smaller and fainter than the primary not to affect the calculation of its physical properties. The mass is estimated to be 113  M☉ and the luminosity over two million  L☉. Although the star is very young, around 1.5 million years old, it has already lost a considerable fraction of its initial mass. The initial mass is estimated to have been 137 M☉, meaning it has lost 24 M☉. [2]

See also

Related Research Articles

Wolf–Rayet star Stars with unusual spectra showing prominent broad emission lines of highly ionised helium and nitrogen or carbon

Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface enhancement of heavy elements, depletion of hydrogen, and strong stellar winds. The surface temperatures of known Wolf-Rayet stars range from 20,000 K to around 210,000 K, hotter than almost all other kinds of stars. They were previously called W-type stars referring to their spectral classification.

NGC 3603 Open cluster in the constellation Carina

NGC 3603 is a nebula situated in the Carina–Sagittarius Arm of the Milky Way around 20,000 light-years away from the Solar System. It is a massive H II region containing a very compact open cluster HD 97950.

Sher 25 Star in the constellation Carina

Sher 25 is a blue supergiant star in the constellation Carina, located approximately 25,000 light years from the Sun in the H II region NGC 3603 of the Milky Way. It is a spectral type B1Iab star with an apparent magnitude of 12.2. Its initial main sequence mass is calculated at 60 times the mass of our Sun, but a star of this type will have already lost a substantial fraction of that mass. It is unclear whether Sher 25 has been through a red supergiant phase or has just evolved from the main sequence, so the current mass is very uncertain.

NGC 3603-A1 Double-eclipsing binary star system in the constellation Carina

NGC 3603-A1 is a double-eclipsing binary star system located at the centre of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. Both stars are of spectral type WN6h and among the most luminous and most massive known.

HD 97950 Star system in the constellation Carina

HD 97950, is a multiple star system and part of a super star cluster within the NGC 3603 H II region. It was catalogued as a single star although it was always known to be a compact cluster. It is now resolved into a massive multiple star at the centre of one of the densest clusters in the galaxy.

HD 5980 Triple star system in the constellation Tucana

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.

AB7 Binary star in the Small Magellanic Cloud in the constellation Tucana

AB7, also known as SMC WR7, is a binary star in the Small Magellanic Cloud. A Wolf–Rayet star and a supergiant companion of spectral type O orbit in a period of 19.56 days. The system is surrounded by a ring-shaped nebula known as a bubble nebula.

R136a2 Star in the constellation Dorado

R136a2 is a Wolf-Rayet star residing near the center of the R136, the central concentration of stars of the large NGC 2070 open cluster in the Tarantula Nebula, a massive H II region in the Large Magellanic Cloud which is a nearby satellite galaxy of the Milky Way. It has one of the highest confirmed masses and luminosities of any known star, at about 187 M☉ and 5.6 million L☉ respectively.

R136c Star in the constellation Dorado

R136c is a star located in R136, a tight knot of stars at the centre of NGC 2070, an open cluster weighing 450,000 solar masses and containing 10,000 stars. At 142 M☉ and 3.8 million L☉, it is the one of the most massive star known and one of the most luminous, along with being one of the hottest, at over 40,000 K. It was first resolved and named by Feitzinger in 1980, along with R136a and R136b.

HD 38282 is a massive spectroscopic binary star in the Tarantula Nebula, consisting of two hydrogen-rich Wolf-Rayet stars.

NGC 3603-B Star in the constellation Carina

NGC 3603-B is a Wolf-Rayet star located at the centre of the HD 97950 cluster in the NGC 3603 star-forming region, about 25,000 light years from Earth. It has the spectral type WN6h and is among the most luminous and most massive stars known.

Melnick 34 Binary wolf rayet star in the constellation Dorado

BAT99-116 is a binary Wolf–Rayet star near R136 in the 30 Doradus complex in the Large Magellanic Cloud. Both components are amongst the most massive and most luminous stars known, and the system is the most massive known binary system.

WR 42e Star in the constellation Carina

WR 42e is a Wolf–Rayet star in the massive H II region NGC 3603 in the constellation of the Carina. It is around 25,000 light-years or 7,600 parsec from the Sun. WR 42e is one of the most massive and most luminous stars known.

R99 is a star in the Large Magellanic Cloud in the constellation Dorado. It is classified as a possible luminous blue variable and is one of the most luminous stars known.

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.

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.

HD 151932

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.

HD 152408

HD 152408, also known as WR 79a, is a Wolf-Rayet star located in the constellation Scorpius, close to the galactic plane. Its distance is around 2,020 parsecs away from the Earth.

References

  1. 1 2 3 4 Melena, Nicholas W.; Massey, Philip; Morrell, Nidia I.; Zangari, Amanda M. (2008). "The Massive Star Content of NGC 3603". The Astronomical Journal. 135 (3): 878–891. arXiv: 0712.2621 . Bibcode:2008AJ....135..878M. doi:10.1088/0004-6256/135/3/878. ISSN   0004-6256. S2CID   16765414.
  2. 1 2 3 4 5 6 7 8 9 10 Crowther, P. A.; Schnurr, O.; Hirschi, R.; Yusof, N.; Parker, R. J.; Goodwin, S. P.; Kassim, H. A. (2010). "The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 M⊙ stellar mass limit". Monthly Notices of the Royal Astronomical Society . 408 (2): 731–751. arXiv: 1007.3284 . Bibcode:2010MNRAS.408..731C. doi:10.1111/j.1365-2966.2010.17167.x. S2CID   53001712.
  3. 1 2 Zacharias, N.; et al. (2003). "The Second U.S. Naval Observatory CCD Astrograph Catalog (UCAC2)". CDS/ADC Collection of Electronic Catalogues. 1289. Bibcode:2003yCat.1289....0Z.
  4. 1 2 Schnurr, O.; Casoli, J.; Chené, A. -N.; Moffat, A. F. J.; St-Louis, N. (2008). "The very massive binary NGC 3603-A1". Monthly Notices of the Royal Astronomical Society: Letters. 389 (1): L38–L42. arXiv: 0806.2815 . Bibcode:2008MNRAS.389L..38S. doi:10.1111/j.1745-3933.2008.00517.x. S2CID   15660536.
  5. ↑ Van Den Bos, W. H. (1928). "Another nebulous multiple star". Bulletin of the Astronomical Institutes of the Netherlands. 4: 261. Bibcode:1928BAN.....4..261V.
  6. ↑ Moffat, Anthony F. J.; Drissen, Laurent; Shara, Michael M. (1994). "NGC 3603 and its Wolf-Rayet stars: Galactic clone of R136 at the core of 30 Doradus, but without the massive surrounding cluster halo". Astrophysical Journal. 436: 183. Bibcode:1994ApJ...436..183M. doi:10.1086/174891.
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