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Collection:
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NASA Great Images in Nasa Collection
Collection
NASA Great Images in Nasa Collection
Collection
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Title:
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Variable Stars in a Distant Spiral Galaxy
Title
Variable Stars in a Distant Spiral Galaxy
Title
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Full Description:
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A NASA Hubble Space Telescope (HST) view of the magnificent spiral galaxy NGC 4603, the most distant galaxy in which a special class of pulsating stars called Cepheid variables have been found. It is associated with the Centaurus cluster, one of the most massive assemblages of galaxies in the nearby universe. The Local Group of galaxies, of which the Milky Way is a member, is moving in the direction of Centaurus at a speed of more than a million miles an hour under the influence of the gravitational pull of the matter in that direction. Clusters of young bright blue stars highlight the galaxy's spiral arms. In contrast, red giant stars in the process of dying are also found. Only the very brightest stars in NGC 4603 can be seen individually, even with the unmatched ability of the Hubble Space Telescope to obtain detailed images of distant objects. Much of the diffuse glow comes from fainter stars that cannot be individually distinguished by Hubble. The reddish filaments are regions where clouds of dust obscure blue light from the stars behind them. This galaxy was observed by a team affiliated with the HST Key Project on the Extragalactic Distance Scale. Because NGC 4603 is much farther away than the other galaxies studied with Hubble by the Key Project team, 108 million light-years, its stars appear very faint from the Earth, and so accurately measuring their brightness, as is required for distinguishing the characteristic variations of Cepheids, is extremely difficult. Determining the distance to the galaxy required an unprecedented statistical analysis based on extensive computer simulations.
Full_Description
A NASA Hubble Space Telescope (HST) view of the magnificent spiral galaxy NGC 4603, the most distant galaxy in which a special class of pulsating stars called Cepheid variables have been found. It is associated with the Centaurus cluster, one of the most massive assemblages of galaxies in the nearby universe. The Local Group of galaxies, of which the Milky Way is a member, is moving in the direction of Centaurus at a speed of more than a million miles an hour under the influence of the gravitational pull of the matter in that direction. Clusters of young bright blue stars highlight the galaxy's spiral arms. In contrast, red giant stars in the process of dying are also found. Only the very brightest stars in NGC 4603 can be seen individually, even with the unmatched ability of the Hubble Space Telescope to obtain detailed images of distant objects. Much of the diffuse glow comes from fainter stars that cannot be individually distinguished by Hubble. The reddish filaments are regions where clouds of dust obscure blue light from the stars behind them. This galaxy was observed by a team affiliated with the HST Key Project on the Extragalactic Distance Scale. Because NGC 4603 is much farther away than the other galaxies studied with Hubble by the Key Project team, 108 million light-years, its stars appear very faint from the Earth, and so accurately measuring their brightness, as is required for distinguishing the characteristic variations of Cepheids, is extremely difficult. Determining the distance to the galaxy required an unprecedented statistical analysis based on extensive computer simulations.
Full Description
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Date:
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05/01/1999
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NASA Center:
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Hubble Space Telescope Center
NASA_Center
Hubble Space Telescope Center
NASA Center
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Subject Category:
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Deep Space Studies
Subject_Category
Deep Space Studies
Subject Category
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Subject Category:
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Hubble
Subject_Category
Hubble
Subject Category
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Keywords:
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Space
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Keywords:
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Telescope
Keywords
Telescope
Keywords
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Keywords:
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Hubble
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Keywords:
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HST
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Keywords:
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Milky
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Keywords:
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Way
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Keywords:
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Spiral
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Keywords:
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NGC
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Keywords:
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Galaxy
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Keywords:
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4603
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Keywords:
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Pulsar
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Keywords:
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Cepheid
Keywords
Cepheid
Keywords
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Keywords:
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Centaurus
Keywords
Centaurus
Keywords
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Audience:
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General Public
Audience
General Public
Audience
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facet_what:
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Earth
facet_what
Earth
facet_what
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facet_what:
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Centaurus
facet_what
Centaurus
facet_what
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facet_what:
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Hubble Space Telescope (HST)
facet_what
Hubble Space Telescope (HST)
facet_what
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facet_when:
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05-01-1999
facet_when
05-01-1999
facet_when
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facet_when_year:
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1999
facet_when_year
1999
facet_when_year
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Image #:
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PR99-19
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original_url:
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original_url
original_url
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UID:
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SPD-GRIN-GPN-2000-00 0940
UID
SPD-GRIN-GPN-2000-00 0940
UID
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Center:
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HSTI
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Center Number:
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PR99-19
Center_Number
PR99-19
Center Number
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GRIN DataBase Number:
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GPN-2000-000940
GRIN_DataBase_Number
GPN-2000-000940
GRIN DataBase Number
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Creator-Photographer:
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NASA, HST Key Project Team
Creator-Photographer
NASA, HST Key Project Team
Creator-Photographer
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Original Source:
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DIGITAL
Original_Source
DIGITAL
Original Source
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