Researchers from the Institute of Physics and Astronomy at the University of Potsdam, led by Roel R. Lefever and Andreas A. C. Sander, have conducted a study on a specific type of massive stars known as Wolf-Rayet (WR) stars, with a focus on nitrogen-rich WN4b stars. Their work, titled “Dynamically consistent analysis of Galactic WN4b stars,” was published in the journal Astronomy & Astrophysics.
Wolf-Rayet stars are known for their strong stellar winds, which can obscure the underlying star and make it challenging to determine key parameters such as stellar radius and atmospheric structure. The researchers employed advanced hydrodynamically-consistent modeling using the PoWR-HD code to break through these challenges and gain new insights into these stars.
The team selected a sample of six Galactic WN4b stars for their study. By applying updated parallaxes from the Gaia DR3 catalog and creating PoWR-HD models that closely matched the spectral appearance of these stars, the researchers were able to obtain new values for the stellar and wind parameters. Notably, they found a narrow range of stellar temperatures around 140,000 Kelvin, in contrast to previous studies. This indicates that the stars in their sample are less luminous and less massive than previously thought, with some having luminosities as low as log L/Lsol = 5.0 and masses around 5 times that of the Sun.
One of the key findings of the study was the identification of a plateau feature in the velocity fields of all six stars, occurring at approximately 85% of the terminal velocity. This feature had not been previously observed and provides new insights into the wind structure of these stars. The researchers also compared their results with stellar structure predictions from GENEC and FRANEC evolution tracks, further validating their findings.
The study also had implications for mass-loss descriptions of WR stars. The researchers found that the mass-loss rates derived for the WN4b sample favored a different description than that for WN2 stars analyzed with the same methodology. This suggests that different types of WR stars may have different mass-loss mechanisms, which could have significant implications for our understanding of stellar evolution.
In summary, this research provides a more accurate and detailed understanding of the parameters and wind structures of WN4b stars. The findings have practical applications for the energy sector, particularly in the field of nuclear fusion research. Understanding the life cycles and properties of massive stars like Wolf-Rayet stars can provide valuable insights into the processes that drive stellar evolution and the production of the elements that make up our universe. This knowledge can, in turn, inform the development of new technologies and approaches for harnessing the power of nuclear fusion, which has the potential to provide a clean, abundant, and sustainable source of energy for future generations.
This article is based on research available at arXiv.