Asymptotic giant branch

<p>The asymptotic giant branch (AGB) is a region of the <a href="/facts/Hertzsprung%25E2%2580%2593Russell_diagram/53YWnCvR">Hertzsprung–Russell diagram</a> populated by evolved cool luminous <a href="/facts/Star/PFbd6ICx">stars</a>. This is a period of <a href="/facts/Stellar_evolution/Qa4vAGmn">stellar evolution</a> undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) late in their lives.
</p><p>Observationally, an asymptotic-giant-branch star will appear as a bright <a href="/facts/Red_giant/lla6Bsvy">red giant</a> with a <a href="/facts/Luminosity/1tdhpk9l">luminosity</a> ranging up to thousands of times greater than the Sun. Its interior structure is characterized by a central and largely inert core of carbon and oxygen, a shell where helium is undergoing fusion to form carbon (known as <a href="/facts/Helium_burning/wV6lacSF">helium burning</a>), another shell where hydrogen is undergoing fusion forming helium (known as <a href="/facts/Hydrogen_burning/qEQJdJe6">hydrogen burning</a>), and a very large envelope of material of composition similar to main-sequence stars (except in the case of <a href="/facts/Carbon_stars/zK6vSgYn">carbon stars</a>).
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Asymptotic giant branch open-in-new

Asymptotic giant branch