Cepheid variable
Cepheid variable One of an important group of yellow giant or supergiant
pulsating variables, named after the prototype, Delta Cephei. This general term is commonly applied to more than one stellar type, in particular to the
classical Cepheids (sometimes known as
Delta Cephei stars), and the less numerous
W Virginis stars.
The significance of Cepheid variables became apparent when H. S.
Leavitt discovered that their period was directly related to their absolute magnitude. The resulting
period-luminosity relationship is used to determine distances. Subsequent work established the existence of two distinct types, with essentially parallel period–luminosity relationships. The classical Cepheids are Population I objects with absolute magnitudes 0.7–2 mag. brighter than the Population II W Virginis stars, as well as larger masses and greater metallicity. Both types undergo
radial pulsations in the
fundamental mode. At maximum size, Cepheids are typically 7–15% larger than at minimum size.
In the past, other distinct types were regarded as forms of Cepheids, notably those called
dwarf Cepheids (
AI Velorum and
Delta Scuti stars), and
short-period Cepheids (
RR Lyrae stars). See also
beat cepheid;
bump cepheid;
double-mode variable.
Cite this article
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Analysis of Data Gathered by Hipparcos Satellite on Cepheid Variable Stars.(Brief Article)
Magazine article from: Bulletin of the South Carolina Academy of Science; 1/1/2001; ; 626 words
; ...Quantifying the shapes of Cepheid variable star light curves is...curves of 135 classical Cepheids observed by Hipparcos...light curve. For those Cepheids with adequate phase...warranted in the study of Cepheid variable stars. Kwayera Davis...
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With a twinkle, pulsating stars could deliver signals from ET: neutrino beams may turn Cepheids into messengers.(STORY ONE)
Magazine article from: Science News; 10/11/2008; ; 700+ words
; ...Those stars, known as Cepheid variables, brighten and dim on a regular...Swan Leavitt reported that a Cepheid's maximum brightness depends...are proposing a new use for Cepheids. In an article recently...tinkering with the core of a Cepheid variable using a beam of neutrinos...
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Cepheid Forms Collaboration With Takara Bio Inc. to Commercialize Novel Dry-Formulated Polymerase Reagents in the Life Sciences Market.
PR Newswire; 1/30/2003; 700+ words
; ...has been optimized for use on Cepheid's Smart Cycler(R) and...TM) HS will also utilize Cepheid's proprietary bead lyophilization...improved flexibility in processing variable sample volumes, and more predictable...in a format complementary to Cepheid's systems. This program...
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Cepheid Extends European Product Line With Launch of Xpert(TM) MRSA Test for GeneXpert(R) System.
PR Newswire; 10/26/2006; 700+ words
; ...day seven days a week," said Cepheid Chief Executive Officer John Bishop...hrs) and results can be highly variable. During this period, MRSA may...with no false positives. About Cepheid Cepheid , based in Sunnyvale, Calif...
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Cepheid, Inc.(CPHD) - Quantitative Valuation Report.
M2 Presswire; 2/23/2003; 700+ words
; ...2003-Research and Markets: Cepheid, Inc.(CPHD) - Quantitative...RDATE:02232003 Company Name - Cepheid, Inc. Now you, as an individual...stock valuation. Fundamental variables such as a company's trailing...Forecast Model The predictive variables used in the forecasting models...
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Search of galactic halo yields a treasure trove of variable stars.
M2 Presswire; 9/26/2001; 700+ words
; ...million stars. Many of them are variable stars, whose brightness varies...some surprises." One type of variable stars, Cepheid variables, are useful as "meter sticks...curves and a catalog of the variable stars are available for viewing...
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Giant star may be used to measure distances up to 300 million light years and beyond.
News Wire article from: Asian News International; 6/9/2009; 700+ words
; ...years and beyond. Cepheid variables, which are giant...State. Classical cepheids are bright, but...suspected that ULP cepheids don't evolve the same way as other cepheids. In this study...evidence of a ULP cepheid evolving as a...
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'Secondary' method of measuring distance to galaxies stronger than previously thought
News Wire article from: The Hindustan Times; 9/29/2008; 600 words
; ...For nearby distances, Cepheid variables - bright stars...relationship between how long a Cepheid takes to shrink and grow...suspicion on the capacity of Cepheids as standard candles, according...candles. But unlike the Cepheid variables, the red giant flash isn...It confirms the ...
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Hubble Data Point to Older, Larger Universe
Newspaper article from: The Washington Post; 6/29/1992; ; 700+ words
; ...pulsating stars known as cepheid variables in a faint galaxy called...million light-years away. Cepheids traditionally have been the...in a particular way: Dim cepheids pulse rapidly; very luminous...apparent brightness of a cepheid variable with its true brightness...
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Scientists zeroing in on age of universe Using Hubble telescope, astronomers narrow range to few billion years
Newspaper article from: The Milwaukee Journal Sentinel; 5/10/1996; ; 700+ words
; ...pulsating stars called Cepheid variables found in a cluster of galaxies...brightness in a dozen Cepheid variable stars in distant galaxies. Astronomers have used Cepheid variables to measure distance for many...methods to double-check its Cepheid measurements. One of ...
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Cepheid variable
Book article from: A Dictionary of Astronomy
Cepheid variable One of an important...supergiant pulsating variables , named after the...to the classical Cepheids (sometimes known...significance of Cepheid variables became apparent when...relationships. The classical Cepheids are Population I...At maximum size, ...
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Cepheid variables
Book article from: The Columbia Encyclopedia, Sixth Edition
Cepheid variables , class of variable stars that brighten and dim...the longer its period. All Cepheid variables with the same period have...distances. By observing a Cepheid's period, one can determine...star's distance. Thus Cepheids are important indicators...
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beat Cepheid
Book article from: A Dictionary of Astronomy
beat Cepheid A Cepheid variable that is oscillating in both the fundamental and first...period . Such stars, also known as double-mode Cepheids , account for nearly half of all Cepheids with periods of 2–4 days.
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classical Cepheid
Book article from: A Dictionary of Astronomy
classical Cepheid A Population I Cepheid variable, sometimes known as a Delta Cephei star ; abbr. DCEP...superficially similar W Virginis stars of Population II, classical Cepheids are massive (5–15 solar masses), young bright...
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Cepheid instability strip
Book article from: A Dictionary of Astronomy
Cepheid instability strip The region...several types of pulsating variable star, including Cepheid variables, classical Cepheids, Delta Scuti stars, RR Lyrae...clusters, while classical Cepheids and W Virginis stars lie at...
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