General: Starlight Winds

Hot Stellar Winds:

Wanna get blown away by StarLight?


  • A stellar wind is the continous outflow of gas from the surface of a star. For a hot, massive star -- as described here -- the ultra-violet light at its surface is so intense that it provides a strong upward directed push on the gas. Indeed, this radiation force becomes so strong that it overcomes the inward pull of gravity, so that material is constantly accelerated upwards and ultimately escapes the star, with velocities that can reach 1000 km/s or even more.


Through such starlight-powered winds, many massive stars loose about an earth-mass (and sometimes even more) every year of their life!

It's good that the Solar Wind is not this powerful, then the earth would have been a pretty inhospitable place :-)



Much more details to follow...



Winds from massive stars: Get blown away by Starlight

For stable massive stars with hot surfaces, scattering of spectral-line photons transfers momentum from the star's intense ultra-violet radiation field to the stellar plasma. And since the radiation field is so intense, it provides an upward pushing force so strong that it overcomes the downward pull of gravity. Consequently stellar plasma is accelerated outwards in a so-called stellar wind, and ultimately the gas escapes the star with velocities reaching 1000 km/s or even more.


Through such starlight-powered winds, these massive monsters to stars loose about an earth-mass to interstellar space during every year of their lives!


As a reference, this is about 100 000 000 times more than the sun looses every year through its solar wind — it’s good for us the sun’s wind is pretty weak, otherwise the Earth would be pretty inhospitable :-)




To be continued, with more details on various aspects of these line-radiation driven winds…..