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White Dwarfs Migrating from Globular Cluster 47 Tucanae’s Core
The heart of the giant globular star cluster 47 Tucanae in the Hubble Space Telescope image at left reveals the glow of 200,000 stars. The green box outlines the cluster's crowded core, where Hubble spied a parade of young white dwarfs starting their slow-paced 40-million-year journey to the less populated suburbs.
White dwarfs are the burned-out relics of stars that rapidly lose mass, cool down, and shut off their nuclear furnaces. As these glowing carcasses age and shed weight, their orbits begin to expand outward from the cluster's packed downtown. This migration is caused by a gravitational tussle among stars in the cluster.
The stellar relics are too faint to be seen clearly in visible light, as shown in the Hubble image at top right. But in ultraviolet light the stars glow brightly because they are extremely hot, as shown in the image at bottom right, taken by Hubble's Wide Field Camera 3. The green circles in the image outline the brightest of the young white dwarfs spied by Hubble.
Astronomers used Hubble to analyze 3,000 white dwarfs in the cluster, located 16,700 light-years away in our Milky Way galaxy's southern constellation of Tucana. Until these Hubble observations, astronomers had never seen the dynamical conveyor belt in action. The Wide Field Camera 3 observations were taken between November 2012 and December 2013. The left-hand image and the image at top right are a blend of exposures taken by the Advanced Camera for Surveys and Wide Field Camera 3.
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.00h 24m 5.35s
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.-72° 4' 53.17"
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Tucana
- DistanceDistanceThe 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.16,700 light-years (5,100 parsecs)
About the Data
- Data DescriptionData 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.The optical/UV image of 47 Tuc was created from Hubble data from proposal 10048, PI: J. Mack and R. Gillian (STScI) and 12311, PI: G. Piotto (University of Padova, Italy) et al. The UV image of 47 Tuc was created from Hubble data from proposal 12971: H. Richer (University of British Columbia), A. Dotter (Australian National University), R. Goldsbury (University of British Columbia), B. Hansen (UCLA), J. Heyl (University of British Columbia), J. Kalirai (STScI/JHU), K. Woodley (University of British Columbia), and K. Sigurdson (University of California, Santa Cruz). The science team includes: J. Heyl and H. Richer (University of British Columbia), E. Antolini (Università degli Studi di Perugia, Italy), R. Goldsbury (University of British Columbia), J. Kalirai (STScI/JHU), J. Parada (University of British Columbia), and P.-E. Tremblay (STScI). - InstrumentInstrumentThe science instrument used to produce the data.HST>ACS/WFC and HST>WFC3/UVIS
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.November 2003 - September 2004, November 2010, and November 2012 - September 2013
- FiltersFiltersThe camera filters that were used in the science observations.Left and Top Right Panels: ACS/WFC: F475W (B), F606W (V), F814W (I) WFC3: F275W (UV) Bottom Right Panel: WFC3: F225W (UV) and F336W (U)
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.47 Tuc, 47 Tucanae, NGC 104
- Object DescriptionObject DescriptionThe type of astronomical object.Globular Cluster
- Release DateMay 14, 2015
- Science ReleaseHubble Catches a Stellar Exodus in Action
- Credits
Left and Top Right Panels: This image is a composite of separate exposures acquired by the ACS/WFC and WFC3 instruments. 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: F475W (B) Green: F606W (V) Red: F814W (I) Purple: F275W (UV) Bottom Right Panel: This image is a composite of separate exposures acquired by the WFC3 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: Cyan: F225W (UV) Yellow: F336W (U)
Related Images & Videos
White Dwarf Migration in Globular Cluster 47 Tucanae (with title)
This diagram shows how white dwarfs, the burned-out relics of stars, are distributed in the ancient globular star cluster 47 Tucanae. The youngest white dwarfs are the hottest and bluest stars dwelling mostly in the cluster's core, where the most massive stars reside. Shortly...
White Dwarf Migration in Globular Cluster 47 Tucanae
This diagram shows how white dwarfs, the burned-out relics of stars, are distributed in the ancient globular star cluster 47 Tucanae. The youngest white dwarfs are the hottest and bluest stars dwelling mostly in the cluster's core, where the most massive stars reside. Shortly...
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Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
