Originally posted by Math Is Hard
Oh, ok, that makes sense now. The hydrogen has already been depleted. Thanks!
Originally posted by Math Is Hard
hmmm... well, I only know a tiny bit about this, but I am told that white dwarves have a mass limit, and that once they reach this limit they become unstable and undergo a gravitational collapse. But I am not sure how a white dwarf gets to that limit and what exactly is causing the mass increase.
Type Ia supernovae are produced when a white dwarf sucks matter off of a red giant companion, reinitiating fusion. The entire white dwarf is literally blown to bits -- there is no compact object (neutron star or black hole) left over, like there can be in Type I or II supernovae.
Originally posted by mathman
The mass increase eventually (fusion is irrelevant) will reach the point where it cannot remain a white dwarf, and collapses into a neutron star. This triggers the type Ia explosion.
Originally posted by Ambitwistor
Type Ia supernovae are produced when a white dwarf sucks matter off of a red giant companion, reinitiating fusion. The entire white dwarf is literally blown to bits -- there is no compact object (neutron star or black hole) left over, like there can be in Type I or II supernovae.
A link:
http://www.astronomyinfo.pwp.blueyonder.co.uk/Supernova.htm
Originally posted by theEVIL1
I think you mean in a Type II SN. NO Type I leaves anything behind as the Core is converted into energy.
They all undergo gravitational collapse; this is where the "initiating" energy comes from.Originally posted by Ambitwistor
Thanks. I was hedging: I thought I remembered reading that some type I (not Ia) supernovae could undergo gravitational collapse (do you know if this is true?), so I thought there might be something left over.
A type 1a supernova is a type of stellar explosion that occurs in a binary star system where one star is a white dwarf. The white dwarf accretes mass from its companion star until it reaches a critical mass, causing a runaway nuclear fusion reaction and resulting in a bright explosion.
The absence of hydrogen in the spectrum of a type 1a supernova is significant because it indicates that the progenitor star was a white dwarf, as opposed to a massive star. Massive stars, which are responsible for other types of supernovae, contain hydrogen in their outer layers, while white dwarfs do not have any hydrogen left after their formation.
Scientists use spectroscopy to determine the composition of a type 1a supernova. They analyze the light emitted from the explosion and look for specific absorption lines that correspond to different elements. The absence of hydrogen in the spectrum indicates a lack of hydrogen in the explosion, confirming the white dwarf origin.
One possible explanation is that the white dwarf had already lost its outer layers of hydrogen through stellar winds before the explosion occurred. Another explanation is that the white dwarf may have accreted material from its companion star that had already lost its hydrogen, or that the explosion was too violent and destroyed any remaining hydrogen.
The absence of hydrogen in type 1a supernova spectra provides evidence for the theory that these explosions are caused by white dwarfs in binary systems. This helps astronomers better understand the life cycle of stars and the processes that lead to supernovae. Additionally, type 1a supernovae have been used as standard candles to measure the expansion of the universe, so understanding their composition is crucial for accurate cosmological models.