Wolf–Rayet stars

✅ Supernova explosion traced to one of the hottest kind of stars.

✅ What’s in News?

◆ Indian astronomers have tracked a rare supernova explosion and traced it to one of the hottest kind of stars called Wolf–Rayet stars or WR stars.

◆ A team of astronomers from Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, with some international collaborators have conducted optical monitoring of a stripped-envelope supernova called SN 2015dj hosted in the galaxy NGC 7371 which was spotted in 2015.

◆ They calculated the mass of the star that collapsed to form the supernovae as well as the geometry of its ejection.

◆ The scientists also found that the original star was a combination of two stars – one of them is a massive WR star and another is a star much less in mass than the Sun.

✅ WR Star:

◆ The rare Wolf–Rayet stars are highly luminous objects a thousand times that of the Sun.

◆ They are massive stars and strip their outer hydrogen envelope which is associated with the fusion of helium and other elements in the massive core.

◆ They are a heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon.

◆ The surface temperatures of known Wolf-Rayet stars range from 30,000 K to around 210,000 K, hotter than almost all other kinds of stars.

◆ They were previously called W-type stars.