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.
Credits
NASA, ESA, and the Hubble Heritage Team (STScI/AURA);Acknowledgment: T. Do and A. Ghez (UCLA), and V. Bajaj (STScI)
| About The Object | |
|---|---|
| Object Name | Galactic Center |
| Object Description | Center of the Milky Way Galaxy |
| R.A. Position | 17h 45m 36.0s |
| Dec. Position | -28° 55' 58.8" |
| Constellation | Sagittarius |
| Distance | 27,000 light-years (8,000 parsecs) |
| About The Data | |
| Data Description | The HST data were taken from proposals , , and PI: T. Do (UCLA) and PI: A. Ghez (UCLA). The science team comprises T. Do, A. Ghez, and M. Morris (UCLA), R. Schodel (Instituto de Astrofísica de Andalucia), J. Lu (University of Hawaii), W. Clarkson (University of Michigan), D. Merritt (RIT), B. Hansen and S. Yelda (UCLA), J. Bullock (University of California, Irvine), J. Anderson (STScI), L. Meyer, E. Mills, and N. McCrady (UCLA), and J.-U. Pott (Max Planck Insititue for Astronomy, Heidelberg). |
| Instrument | HST>WFC3/IR |
| Exposure Dates | 2010 - 2014 |
| Filters | F127M (H2O/CH4 continuum), F139M (H2O/CH4 line), and F153M (H2O and NH3) |
| About The Image | |
| Color Info | This image is a composite of separate exposures acquired by the WFC3/IR instrument. Several filters were used to sample various wavelengths. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F127M (H2O/CH4 continuum) Green: F139M (H2O/CH4 line) Red: F153M (H2O and NH3) |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
