R136a3
A massive Wolf–Rayet star in the R136 cluster.
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R136a3 is a Wolf–Rayet star located in the R136 star cluster, which lies in the Dorado constellation. It is one of the most massive and most luminous stars known, with a mass about 184 times that of the Sun and a luminosity roughly 5 million times greater. The star is situated near R136a1, the most massive and luminous star known.
Quick Facts
- Spectral type
- Wolf–Rayet (emission lines of helium and nitrogen)
- Surface hydrogen content
- 40%
- Location
- R136 cluster, Dorado
- Formal designation
- RMC 136a3
Facts from the source article.
Lore & Background
R136a3 is formally designated RMC 136a3, from the Radcliffe Observatory Magellanic Clouds survey that identified luminous objects in the Large Magellanic Cloud. One of the brightest was RMC 136, now shortened to R136, an extremely young dense open cluster at the core of the NGC 2070 cluster in the Tarantula Nebula. The brightest central 'star' was termed R136a, later resolved into multiple components, one of which is R136a3.
Despite its Wolf–Rayet spectral type—characterized by intense emission lines of helium and nitrogen, usually indicating a highly evolved star that has lost its outer layers—R136a3 is actually an extremely young star. Its spectrum also includes hydrogen lines, and analysis shows the star is still 40% hydrogen at the surface. The helium and nitrogen in its atmosphere are caused by strong convection due to the massive core and intense CNO cycle fusion, enhanced further by rotational mixing. The emission lines indicate strong mass loss caused by the fusion products at the surface and the enormous luminosity.
Reader's Guide
R136a3 is notable as one of the most massive and luminous stars known, with a mass of about 184 solar masses and a luminosity 5 million times that of the Sun. Its location in the R136 cluster, near the record-holding star R136a1, places it at the heart of one of the most extreme stellar environments in the Local Group. The star challenges conventional understanding of Wolf–Rayet evolution: its spectral type typically signals an evolved star that has shed its outer layers, yet R136a3 is extremely young and retains 40% hydrogen at its surface.
This paradox is explained by deep convection and rotational mixing driven by its enormous core, which bring fusion products to the surface early in its life. The intense emission lines and strong mass loss observed in its spectrum are direct consequences of its extreme luminosity and surface composition. R136a3 thus serves as a key example of how the most massive stars can exhibit Wolf–Rayet characteristics while still in their youth, providing insight into the early evolution of stars near the theoretical upper mass limit.
More in Emission, Dark and Reflection Nebulae
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: R136a3 (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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