NGC 3603-C

NGC 3603-C (HD 97950C, WR 43c) is a spectrally binary star in the central part of the HD 97950 cluster in the star forming region NGC 3603 , located at a distance of about 20,000 light years from the Sun. The primary component belongs to the spectral class WN6h and is one of the most massive and brightest known stars.

NGC 3603-C
Star
C is the brightest star to the left of closely located stars A and B in the central part of the HD 97950 cluster obtained by the Hubble telescope .
Observational data ( Age J2000.0)
Type of	Wolf-Rayet star
Right ascension
Declination
Distance	7,600 pc [2]
Visible magnitude ( V )	11.89 [1]
Constellation	Keel
Astrometry
Own movement (μ)	RA: 2.4 [3] Dec: 2,8 [3]
Absolute magnitude (V)	-7.17 [2]
Specifications
Spectral class	WN6h +? [2]
Color Index ( B - V )	1.05 [1]
Variability	spectral double star
physical characteristics
Weight	113 [2] M ☉
Radius	26.2 [2] R ☉
Age	1.5 million [2] years
Temperature	44,000 [2] K
Luminosity	2,200,000 [2] L ☉
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 Information
SIMBAD	data

Object HD 97950 was initially listed in the catalogs as a star , but it is now known that it is a dense cluster or a close multiple star . In 1926, the most striking stars were assigned the designations from A to F ^[4] , but in subsequent studies, many stars turned out to be composed of several components ^[5] . It was shown that star C is a double star, but no companion star was observed ^[6] .

HD 97950C is a Wolf-Rayet star ; wide emission lines predominate in the spectrum. The spectral class WN6 shows that the lines of ionized nitrogen are strong in comparison with the lines of ionized carbon , the suffix h indicates that hydrogen lines are also present in the spectrum. This type of Wolf-Rayet star is a young object of high luminosity , in which the products of thermonuclear reactions of the CNO cycle are brought to the surface due to mixing of the substance during convection and rotation; in the atmosphere there is an intense loss of matter. Emission lines form in the stellar wind . The fraction of hydrogen on the surface is estimated at 70% ^[2] .

The two components of NGC 3603-C rotate around each other with a period of 9 days. It is assumed that the secondary component is significantly smaller and weaker than the primary, and does not affect the assessment of the physical properties of the star. The mass of the star is estimated at 113 M${\displaystyle {}_{<span><span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">\odot </span></span></span>}}$ {\ displaystyle _ {\ odot}} , luminosity exceeds solar by 2 million times. Despite the fact that the star is young (estimated at 1.5 million years old), it lost a significant portion of its initial mass during evolution. The initial mass of the star is estimated at 137 M${\displaystyle {}_{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">\odot </span></span>}}$ {\ displaystyle _ {\ odot}} that is, the star lost 24 M${\displaystyle {}_{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">\odot </span></span>}}$ {\ displaystyle _ {\ odot}} ^[2] .