NGC 3603-B (HD 97950B) is a
Wolf-Rayet star located at the centre of the
HD 97950
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 th ...
cluster in the
NGC 3603 star-forming region, about 25,000
light years from
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
. It has the spectral type WN6h and is among the
most luminous and
most massive stars known.
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,
although several of them have since been resolved into more than one star. Star B turned out to be the brightest single star.
HD 97950B 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
The CNO cycle (for carbon–nitrogen–oxygen; sometimes called Bethe–Weizsäcker cycle after Hans Albrecht Bethe and Carl Friedrich von Weizsäcker) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, ...
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 around 60%.
[
HD 97950B is the most massive and most luminous star known in the NGC 3603 region, nearly three million times more luminous than the sun and 132 times more massive. Although the star is very young, around 1.5 million years old, it has already lost a considerable fraction of its initial masses. The initial mass is estimated to have been , meaning it has lost .][
]
References
External links
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NASA Image of the day
{{DEFAULTSORT:NGC 3603-B
Carina (constellation)
Wolf–Rayet stars
NGC 3603
097950B
054948B
Durchmusterung objects