| NASA Center: |
Hubble Space Telescope Center |
|---|
| Image # : |
PR99-40 |
|---|
| Date : |
10/26/1999
|
|---|
|
Title
Utraviolet Light Source in an Old Galaxy
Full Description
Hubble Space Telescope's exquisite resolution has allowed astronomers
to resolve, for the first time, hot blue stars deep inside an
elliptical galaxy. The swarm of nearly 8,000 blue stars resembles a
blizzard of snowflakes near the core (lower right) of the neighboring
galaxy M32, located 2.5 million light-years away in the constellation
Andromeda.
Hubble confirms that the ultraviolet light comes from a population of
extremely hot helium-burning stars at a late stage in their lives.
Unlike the Sun, which burns hydrogen into helium, these old stars
exhausted their central hydrogen long ago, and now burn helium into
heavier elements.
The observations, taken in October 1998, were made with the camera mode
of the Space Telescope Imaging Spectrograph (STIS) in ultraviolet
light. The STIS field of view is only a small portion of the entire
galaxy, which is 20 times wider on the sky. For reference, the full
moon is 70 times wider than the STIS field-of-view.
Thirty years ago, the first ultraviolet observations of elliptical
galaxies showed that they were surprisingly bright when viewed in
ultraviolet light. Before those pioneering UV observations, old groups
of stars were assumed to be relatively cool and thus extremely faint in
the ultraviolet. Over the years since the initial discovery of this
unexpected ultraviolet light, indirect evidence has accumulated that it
originates in a population of old, but hot, helium-burning stars. Now
Hubble provides the first direct visual evidence.
Keywords
Hubble Space Telescope HST M32 Constellation Andromeda Space Telescope Imaging Spectrograph STIS
Subject Category
Deep Space Studies, Hubble,
Reference Numbers
- Center:
HSTI
- Center Number:
PR99-40
- GRIN DataBase Number:
GPN-2000-000899
Source Information
- Creator/Photographer: NASA, Thomas M. Brown Charles W. Bowers Randy A. Kimble, Allen V.
- Original Source: DIGITAL
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Updated October 31, 2002
• History Questions: NASA History Office
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