Milky Way Nuclear Star Cluster
Credit: NASA, ESA, HSTWFC3/IR, STScI-PRC16-11a
This four-panel graphic zooms into the Hubble Space Telescope view of
the galactic core. The first panel shows a wide view of the Milky Way in
visible light. The second panel, which zooms into the boxed area in
the first panel, shows interstellar dust obscuring much of the view of
the core. The third panel zooms in yet again, but the view shifts to
infrared light that penetrates the dust and exposes the core. Finally,
the fourth panel is a close-up of the galactic core as seen in infrared
by the Hubble Space Telescope. The locator mark in the middle
designates the galaxy's nucleus, which is home to a central,
supermassive black hole. Credit: NASA, ESA, and Z. Levay (STScI). Acknowledgment: NASA, ESA, A. Fujii, Digitized Sky Survey (DSS), STScI/AURA, Palomar/Caltech, UKSTU/AAO, NASA/JPL-Caltech/S. Stolovy (Spitzer Science Center/Caltech), the Hubble Heritage Team (STScI/AURA), T. Do and A. Ghez (UCLA), and V. Bajaj (STScI)
Hubble's infrared vision pierced the dusty heart of our Milky Way galaxy
to reveal
more than half a million stars at its core. Except for a few blue,
foreground stars, the stars are part of the Milky Way's nuclear star
cluster, the most massive and densest stellar cluster in our galaxy.
Located 27,000 light-years
away, this region is so packed with stars, it is equivalent to having a
million suns crammed into the volume of space between us and our closest
stellar neighbor, Alpha Centauri, 4.3 light-years away. At the very hub
of our galaxy, this star
cluster surrounds the Milky Way's central supermassive black hole, which
is
about 4 million times the mass of our sun.
Peering deep into the heart of our Milky Way galaxy, NASA's Hubble
Space Telescope reveals a rich tapestry of more than half a million
stars. Except for a few blue, foreground stars, the stars are part of
the Milky Way's nuclear star cluster, the most massive and densest star
cluster in our galaxy. So packed with stars, it is equivalent to having
a million suns crammed into the volume of space between us and our
closest stellar neighbor, Alpha Centauri, 4.3 light-years away. At the
very hub of our galaxy, this star cluster surrounds the Milky Way's
central supermassive black hole, which is about 4 million times the
mass of our sun.
Astronomers used Hubble's infrared vision to pierce through the dust
in the disk of our galaxy that obscures the star cluster. In this
image, scientists translated the infrared light, which is invisible to
human eyes, into colors our eyes can see. The red stars are either
embedded or shrouded by intervening dust. Extremely dense clouds of gas
and dust are seen in silhouette, appearing dark against the bright
background stars. These clouds are so thick that even Hubble's infrared
capability could not penetrate them.
Hubble's sharp vision allowed astronomers to measure the movements of
the stars over four years.
Using this information, scientists were
able to infer important properties such as the mass and structure of
the nuclear star cluster. The motion of the stars may also offer a
glimpse into how the star cluster was formed — whether it was built up
over time by globular star clusters that happen to fall into the
galaxy's center, or from gas spiraling in from the Milky Way's disk to
form stars at the core.
This picture, spanning 50 light-years across, is a mosaic stitched
from nine separate images from Hubble's Wide Field Camera 3. The center
of the Milky Way is located 27,000 light-years away. The "snowstorm"
of stars in the image is just the tip of the iceberg: Astronomers
estimate that about 10 million stars in this cluster are too faint to
be captured in this image.
For additional information, contact:
Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu
Zolt Levay
Space Telescope Science Institute, Baltimore, Maryland
410-338-4907
levay@stsci.edu
Tuan Do
University of California, Los Angeles, California
tdo@astro.ucla.edu
Andrea Ghez
University of California, Los Angeles, California
ghez@astro.ucla.edu
Source: HubbleSite
