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News Release Archive:

News Release 302 of 961

December 4, 2007 10:00 AM (EST)

News Release Number: STScI-2007-42

How White Dwarfs Get Their 'Kicks'

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Image: Hubble Finds Young White Dwarfs on the Fast Track

Hubble Finds Young White Dwarfs on the Fast TrackSTScI-PRC2007-42

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ABOUT THIS IMAGE:

These images show young and old white dwarf stars — the burned-out relics of normal stars — in the ancient globular star cluster NGC 6397.

The image at left, taken by a ground-based telescope, shows the dense swarm of hundreds of thousands of stars that make up the globular cluster. The white box outlines the location of the observations made by NASA's Hubble Space Telescope.

The image at top, right, taken by Hubble's Advanced Camera for Surveys, reveals young white dwarfs less than 800 million years old and older white dwarfs between 1.4 and 3.5 billion years old. The photo shows 12 of the 84 white dwarfs in the Hubble study. The blue squares pinpoint the young white dwarfs; the red circles outline the older white dwarfs. The Hubble researchers distinguished the younger from the older white dwarfs based on their color and brightness. The younger white dwarfs are hotter and therefore bluer and brighter than the older ones.

The astronomers were surprised to find young white dwarfs far away from the cluster's core. They had assumed that the youngsters would reside at the center and migrate over time to the cluster's outskirts. The astronomers proposed that the cluster stars that burn out as white dwarfs are given a boost that propels them to the edge of the cluster.

Close-up images of the white dwarfs are shown at bottom, right. The blue boxes represent the young white dwarfs; the red boxes indicate the older white dwarfs.

The ground-based image was taken June 5, 2005. The Hubble images were taken in March and April 2005.

Object Name: NGC 6397

Image Type: Astronomical/Illustration

Credit for Ground-based Image: D. Verschatse (Antilhue Observatory, Chile)

Credit for Hubble Images: NASA, ESA, and H. Richer (University of British Columbia)

NEWS RELEASE IMAGES

The above montage includes these images:

Ground-based Image of Globular Cluster NGC 6397 Image Type: Astronomical Ground-based Image of Globular Cluster NGC 6397 Hubble Space Telescope Image of Globular Cluster NGC 6397 Image Type: Astronomical Hubble Space Telescope Image of Globular Cluster NGC 6397 White Dwarfs in NGC 6397 (Hubble) Image Type: Astronomical White Dwarfs in NGC 6397 (Hubble)

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