The Gaia Stars of M15
Explanation:
Messier 15
is a 13 billion year old relic of the early formative years
of our galaxy, one of about 170 globular star clusters that
still roam the halo of the Milky Way.
About 200 light-years in diameter, it
lies about 35,000
light
years away toward the constellation Pegasus.
But this realistic looking view of the ancient globular star
cluster is not a photograph.
Instead it's an animated gif image constructed from remarkably precise
individual measurements of star positions, brightness, and color.
The astronomically rich data set used was made by the
sky-scanning
Gaia
satellite which also determined
parallax distances for 1.3 billion Milky Way stars.
In the animated gif, twinkling stars are M15's
identified RR Lyrae stars.
Plentiful in M15,
RR Lyrae stars
are evolved pulsating variable stars
whose brightness and pulsation period,
typically less than a day, are related.
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.
