KITP: rapidly rotating stars

stars do turn, sometimes fast enough to be noticeably flattened
this may have consequences

Like So

there are two issues related to stellar rotation contemplated this morning:



Altair



now, way flatter than that...

self-enrichment - back to the good old O/Na anti-correlation
evidence for H burning at high T
trick is not so much to burn the H, but to get the ashes out...

can do that either with AGB stars, yes, it is the dreaded "third dredge up", or just boring old hot bottom burning... ok, don't ever google that.



AGB dredge up (from Eskridge's online lecture notes at MNSU)

anyway, to get the interesting level of enrichment you need to form stars from equatorial outflow of rapidly rotating massive stars, have flat MF and all massive stars rapidly rotating
and/or lose all the low mass stars
ok, that is contrived, even by my standards,
so maybe not

or in massive stars
- do rotational mixing
which is efficient, right, so you get rid of the H layers, right
so we don't get SNII we get SNIb/c - and y'all know that type Ib/c supernovae are actually sub-types of type II but type Ia is absolutely positively definitely not.



bang

nice movie here

maybe, for a mass/rotation paramater range between SNIb and SNIc you get long gamma-ray bursts - for masses ~ 20-30 solar masses, and high enough rotation, and moderate metallicities...

therefore young globular clusters make lots of long gamma ray bursts, right?

Yoon et al 2006
Decressin et al 2007/8

so we conclude that this is impossible and one or both are erroneous?
maybe



Let's not forget magnetic fields...

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