Search for Red Dwarfs in NGC 6397

Left Image

A Hubble Space Telescope image of a small region (1.4 light-years across) in the globular star cluster NGC 6397. Simulated stars (diamonds) have been added to this view of the same region of the cluster to illustrate what astronomers would have expected to see if faint red dwarf stars were abundant in the Milky Way Galaxy. The field would then contain 500 stars, according to theoretical calculations.

Right Image

The unmodified HST image shows far fewer stars than would be expected, according to popular theories of star formation. HST resolves about 200 stars. The stellar density is so low that HST can literally see right through the cluster and resolve far more distant background galaxies. From this observation, scientists have identified the surprising cutoff point below which nature apparently doesn't make many stars smaller that 1/5 the mass of our Sun. These HST findings provide new insights into star formation in our Galaxy.


F. Paresce, ST ScI & ESA and NASA

About the Image

NASA press release
NASA caption
Release date:17 October 1994, 05:00
Size:800 x 600 px

About the Object

Name:NGC 6397
Type:Milky Way : Star : Grouping : Cluster : Globular
Distance:9000 light years
Category:Star Clusters

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Screensize JPEG
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Optical Hubble Space Telescope

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