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Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)

A dramatically crowded starfield that looks like a just-shaken snow globe. The black background of space, which is clearer at the edges, is covered by thousands of tiny white, orange, and blue points of light, which are stars. The stars are most concentrated in the center, forming a roughly circular orb, and sparser at the edges of the image. Several larger orange stars, particularly those largest near the edges of the frame, have prominent diffraction spikes.

Terzan 5 is a stellar system orbiting within the Milky Way galaxy’s bulge, which is an incredibly bright, crowded central region of the galaxy. Not only are stars within the bulge tightly packed together — every bit of this region is laced with thick clouds of gas and dust.

NASA’s James Webb and Hubble Space Telescopes joined forces to study Terzan 5. Astronomers already knew that this star cluster was unusual in that it contained two stellar populations of very different ages. New research found strong evidence for two more stellar populations, one that formed 3.8 billion years ago and another only 2.5 billion years ago. The research team also was able to determine the ages of the previously known stellar populations with unprecedented precision, finding that they formed 12.5 billion and 4.7 billion years ago.

This finding proved that Terzan 5 is not a globular star cluster, as originally classified. Instead, Terzan 5 belongs to a new category, known as a bulge fossil fragment — a self-contained, self-enriching stellar system with multiple star populations of different ages and with different iron abundances.

Terzan 5 is 22,000 light-years away in the constellation Sagittarius. It contains about 2 million times the Sun's mass packed into a stellar system only a few tens of light-years across, making it one of the most massive and densely populated globular-cluster-like systems in the Milky Way.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    17:48:05.00
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    -24:46:48.0
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Sagittarius
  • Distance
    DistanceThe 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.
    22,000 light-years away 
  • Dimensions
    DimensionsThe physical size of the object or the apparent angle it subtends on the sky.
    This image is about 2.1 arcminutes across (13 light-years)

About the Data

  • Data Description
    Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
    Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.

    This image was created with Hubble data from proposal: 12933 (F. R. Ferraro) and Webb data from proposal: 5502 (F. R. Ferraro). 

  • Instrument
    InstrumentThe science instrument used to produce the data.
    Hubble> ACS/WFC Webb> NIRCam
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    19 Sept. 2024, 30 April-18 August 2013
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F606W, F814W, F115W, F200W
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Terzan 5
  • Object Description
    Object DescriptionThe type of astronomical object.
    Bulge fossil fragment stellar group
  • Release Date
    June 16, 2026
  • Science Release
    NASA Webb, Hubble Reveal History of Relic of Milky Way’s Formation
    Read the release
  • Credit
    Image: NASA, ESA, CSA, STScI, Giorgia Zullo (University of Bologna), Francesco Ferraro (University of Bologna); Image Processing: Alyssa Pagan (STScI)

Downloads

  • Full Res (For Print), 4144 × 3031
    tif (35.95 MB)
  • Full Res (For Display), 4144 × 3031
    png (19.8 MB)
  • 4144 × 3031
    jpg (6.46 MB)
  • 2000 × 1463
    jpg (2.24 MB)
A dramatically crowded starfield that looks like a just-shaken snow globe. The black background of space, which is clearer at the edges, is covered by thousands of tiny white, orange, and blue points of light, which are stars. The stars are most concentrated in the center, forming a roughly circular orb, and sparser at the edges of the image. Several larger orange stars, particularly those largest near the edges of the frame, have prominent diffraction spikes.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

These images were acquired by the ACS/WFC instrument on Hubble and the NIRCam instrument on Webb. The color results from assigning different hues (colors) to a monochromatic (grayscale) image. In this case, the assigned colors are: Blue: F606W, Cyan: F814W, Orange: F115W, Red: F200W

Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.

Related Images & Videos

Image titled u201cJames Webb and Hubble Space Telescopes; Terzan 5,u201d with compass arrows and color key. A dramatically crowded starfield that looks like a just-shaken snow globe. The black background of space is covered by thousands of tiny white, orange, and blue points of light, which are stars. The stars are most concentrated in the center, forming a roughly circular orb. At the bottom left are compass arrows indicating the orientation of the image on the sky. The east arrow points toward 12 ou2019clock. The north arrow points toward 3 ou2019clock. At the bottom right is a scale bar labeled 2 light-years. The length of the scale bar is about one seventh of the total image. Below the image is a color key showing which Hubble ACS/WFC and Webb NIRCam filters were used to create the image, and which visible-light color is assigned to each filter. Hubble ACS filters, from left to right: F606W is blue and F814W is teal. Webb NIRCam filters: F115W is orange, F200W is red.

Terzan 5 (Webb and Hubble Compass Image)

This image of bulge fossil fragment Terzan 5 was captured by the James Webb and Hubble space telescopes. Webb’s data are from its NIRCam (Near-Infrared Camera) and Hubble’s from its Advanced Camera for Surveys (ACS). The image shows a scale bar, compass arrows, and co...

Telescope image shows the Milky Way. The Milky Wayu2019s central region runs from top left to bottom right and has dark lanes of dust overlapping bright regions of stars. At the center is a label, Milky Way Center. The entire image is mostly black with pinpoints of light throughout. Thin blue lines connect several stars of two constellations, including the shape of a teapot representing Sagittarius at left and a long, arced line representing Scorpius at right. On the left, a large illustration of a centaur represents Sagittarius, with the teapot over his right arm. On the right, a large illustration of a scorpion represents Scorpius, with the line running throughout the center of its body.

Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge

Zoom in to Terzan 5, a star cluster that lies within the crowded central region of our Milky Way galaxy known as the bulge. The scene starts with a ground-based image of our Milky Way bulge and zooms in on and circles Terzan 5, ending with the composite image of the star system f...

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Details

Last Updated
Jun 15, 2026
Location
NASA Goddard Space Flight Center
Contact
Media

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

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