<p>Are the red Giant branch and the Hayashi track the same thing? After doing some research, I found some similarities between the two, such as both aree fully convective. However, the T Tauri phase does not fuse. But from the outside, are they the same?</p>

CC BY-SA 4.0
2024-03-19T04:28:47.590Z
I think you're asking whether one could confuse one with the other? I don't think so, but not 100% sure. They should be well separated in the HR-diagram. Also Hayashi tracks are pre-main sequence evolution tracks for low-mass stars, and RGB stars are late evolutionary phases of high-mass stars.
AtmosphericPrisonEscape
CC BY-SA 4.0
2024-03-19T21:33:46.770Z
It would really help for you to clear up the intent of the question as they're obviously not the same thing at all. The Hayashi track describes a protostar of low to moderate mass that is still collapsing while the red giant branch describes an ever expanding moderate mass star whose core has been depleted of hydrogen but is fusing hydrogen in a shell around its inert core.
David Hammen
CC BY-SA 4.0
2024-03-19T21:43:36.517Z
BTW, while Hayishi track pre-main sequence stars are fully convective, red giant branch post-main sequence stars are not. The latter have an inert core that for the most part does not mix with the outer part.
David Hammen
<star><stellar-evolution><red-giant><protostar>
Hayashi Track vs Red Giant branch
Astrovis
# Hayashi Track vs Red Giant branch

(Asked by: username_0 on 2024-03-18)

Are the red Giant branch and the Hayashi track the same thing? After doing some research, I found some similarities between the two, such as both aree fully convective. However, the T Tauri phase does not fuse. But from the outside, are they the same?

**Tags:** star, stellar-evolution, red-giant, protostar
> **Comments:**
> **username_1**: I think you're asking whether one could confuse one with the other? I don't think so, but not 100% sure. They should be well separated in the HR-diagram. Also Hayashi tracks are pre-main sequence evolution tracks for low-mass stars, and RGB stars are late evolutionary phases of high-mass stars.  
> **username_2**: It would really help for you to clear up the intent of the question as they're obviously not the same thing at all. The Hayashi track describes a protostar of low to moderate mass that is still collapsing while the red giant branch describes an ever expanding moderate mass star whose core has been depleted of hydrogen but is fusing hydrogen in a shell around its inert core.  
> **username_2**: BTW, while Hayishi track pre-main sequence stars are fully convective, red giant branch post-main sequence stars are not. The latter have an inert core that for the most part does not mix with the outer part.  

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