Hydrogen, Helium, and the Stars of M10
Explanation:
Stars like the Sun use hydrogen for fuel,
"burning" hydrogen into helium at their cores
through nuclear fusion.
But what happens when that hydrogen runs out?
For a while, hydrogen burns in a shell surrounding the stellar core
and the star expands to become a red giant.
The bright reddish-orange stars in
this
beautiful two-color composite
picture of the old
globular
star cluster M10 are examples of this phase
of
stellar evolution.
Yet the bright blue stars apparent in M10 have evolved beyond
the simple, hydrogen shell burning stage.
These stars have become "horizontal branch" giants with
core temperatures hot enough
to burn helium into carbon.
In this image, only the barely visible, faint, gray-looking
stars are likely to still be burning
hydrogen at their cores.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
