M32: Blue Stars in an Elliptical Galaxy
Elliptical galaxies
are known for their old, red stars. But is this old
elliptical up to new tricks?
In recent years, the centers of
elliptical galaxies
have been found to emit unexpectedly high amounts of blue and
ultraviolet light.
Most blue light from
spiral galaxies originates from
massive young hot stars,
in contrast to the red light from the old cool stars
thought to compose ellipticals.
In the
above recently released, false-color photograph by the
Hubble Space Telescope,
the center of nearby dwarf elliptical M32 has actually been
resolved and does indeed show thousands of bright blue stars.
The
answer is probably that
these blue stars are also old and glow blue, reaching relatively
high temperatures by the
advanced process of
fusing helium, rather than
hydrogen, in their cores.
M32 appears in many pictures
as the companion galaxy to the massive
Andromeda Galaxy (M31).