Cepheid Variable
Related Category: Astronomy: General
(s´fd), class of variable stars that brighten and dim in an extremely regular fashion.
Cepheid Variable Stars
Cepheid variable stars were named after the first of their kind observed, δ Cepheus.
Cepheid variables
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Cepheid Variable Stars & Distance Determination
Discovery of the Period - Luminosity Relationship
Calculating Distances Using Cepheids
Standard Candles
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Cepheid Variable
Portions of this entry contributed by Alfred Gautschy
A Cepheid variable is a young of several solar masses and roughly 104 solar luminosities whose luminosity changes periodically.
Cepheid Variable Star :
A Cepheid variable star one of a class of variable stars whose periods (i.e., the time for one cycle) of variation tend to be proportional to their luminosity and that are therefore useful in measuring interstellar and ...
Cepheid Variables as Cosmic Yardsticks
Cepheid stars oscillate between two states: In one of the states, the star is compact and large temperature and pressure gradients build up in the star. These large pressures cause the star to expand.
Cepheid variables are named after Delta Cephei, the first star of this type to be discovered. It was discovered in 1784 by John Goodricke, a deaf and mute English astronomer. It has a period of 5.4 days, less than any variable star known at the time.
Definition: Cepheid Variable: A type of variable star which exhibits a regular pattern of changing brightness as a function of time. The period of the pulsation pattern is directly related to the star's intrinsic brightness.
Cepheid Variable Stars
Cepheid variable stars are stars that periodically pulsate because of an instability in their internal structure.
Cepheid variable Star whose luminosity varies in a characteristic way, with a rapid rise in brightness followed by a slower decline.
Cepheid variables: On 1st January 1925 at a joint meeting of the American Astronomical Society and the American Association for the Advancement of Science, ...
Cepheid variables. These are supergiants in the instability strip on the H-R diagram, undergoing regular pulsations that are expressed by luminosity and temperature variations.
Cepheid Variable Stars: A luminous giant star whose brightness varies periodically: growing very bright quickly, and then dimming slowly. The period of variation is related to luminosity.
Cepheid variable- a variable star of short period; the fluctuations are regular and are linked with its real luminosity; the longer the period, the more luminous the star ...
Cepheid Variable Star
Variable stars with a period of 1-60 days. Their period is related to luminosity.
Chandrasekhar Limit ...
Cepheid variable
A variable star whose luminosity and period are related, and are used as an indicator of the star's distance.
CEPHEID VARIABLE - Star whose luminosity and other parameters vary in a characteristic way (below), with a rapid rise in brightness followed by a slower decline.
Cepheid Variable - A member of a class of yellow pulsating stars that vary in brightness as they expand and contract. The period of a Cepheid is related to its luminosity ...
Cepheid Variable
(a) A type of variable star whose period of variation is tightly related to its intrinsic luminosity.
(b) A class of stars named after Delta Cephei which vary in brightness over a regular period of time (typically a few days).
A Cepheid Variable Star
Polaris A is a pulsating variable star of a type known as a Cepheid variable, after prototypical star of this type, Delta Cephei. Cepheid variables are bright, giant stars that show periodic variations in luminosity.
STARS, CEPHEID VARIABLE, PERIOD-LUMINOSIRY RELATION AND DISTANCE SCALE
Barry F. Madore and Wendy L. Freedman ...
Cepheid Variable
A type of pulsating star whose light and energy output vary noticeably over a set period of time.
Cepheid variable star: A star with periodic variations in magnitude (brightness).
Challenger: The second space shuttle to be launched into orbit. It was destroyed in 1986 after an explosion occurred a few seconds into flight.
Cepheid variables (ok to ~ 1 Mpc)
further, need bright ``standard candles''
eg brightest stars, HII regions, supernovae
Velocity of galaxies (almost all redshifts)
Hubble diagram : velocity (km/s) versus distance (Mpc) ...
cepheid variable - A star that belongs to one of two classes (type I and type II) of yellow supergiant pulsating stars.
Cepheid Variable Stars: A type of luminous giant star whose luminosity varies in a periodic fashion. Cepheids are characterized by a rapid rise in luminosity followed by a slow decline.
Cepheid variables are dimmer than the Type I supernova. As a result, the supernova allows us to measure the distances of galaxies further away, but it happens much less often. Each one has its advantages and disadvantages.
Cepheid Variable
This is a variable star whose light pulsates in a regular cycle. The period of fluctuation is linked to the brightness of the star. Brighter Cepheids will have a longer period.
Chaos
A distinctive area of broken terrain.
Cepheid variable - (n.)
A type of supergiant star that oscillates in brightness in a manner similar to the star 8 Cephei.
- Cepheid Variable - Space and Astronomy Definition - Online Dictionary and Glossary Definition of Cepheid Variable
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A Cepheid variable; magnitude range 5.4 to 6.6, period 3.7 days
T Aur
star ...
Using the Cepheid variable method, an estimate of 2.51 ± 0.13 Mly (770 ± 40 kpc) was achieved in 2004.
RR Lyrae and Cepheid variable stars are recognizable by the characteristic shapes of their light curves.
Cepheid variable. These are blow-ups of pictures taken by the Hubble Space Telescope last year. Notice how the star fades in and out.
N. pole star; Cepheid variable; triple, F7 dwarf close, F3 distant
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Nunki ...
Eta Aquilae is a cepheid variable: 3.48-4.39 with a period of 7.18 days (more precisely 7 days, 4 hours, 14 minutes and 21.8 seconds).
Some Cepheid variable stars can be found in this constellation: W Sgr is a supergiant which brightness fluctuates every 7 days and 14 hours between 4.4 mag and 5.0 mag.
The supergiant (spectraltype G1.5Ib) U Sgr lies close to center of M25.
period-luminosity relation how the average luminosity of Cepheid variable stars depends on their period of pulsation. photon a distinct ``chunk'' or particle of electromagnetic radiation.
A special class of stars exists, the Cepheid variables, which vary in brightness in periods that depend on their intrinsic intensities.
If one requires the distance to a given galaxy one first locates the Cepheid variables in this galaxy. From these observations one determines the period of each of these stars.
1784 - Edward Piggot discovers the first Cepheid variable star
1838 - Thomas Henderson, Friedrich Struve, and Friedrich Bessel measure stellar parallaxes ...
A nearly vertical region of the HR diagram, known as the instability strip, is occupied by pulsating variable stars known as Cepheid variables. These stars vary in magnitude at regular intervals, giving them a pulsating appearance.
In 1912, Henrietta Leavitt discovered what is known as the Period-Luminosity Relationship for Cepheid variables, by which the period of the brightness change is related to the luminosity, and therefore the distance, of the star.
Edwin Hubble settled the debate in 1925 when he identified extragalactic Cepheid variable stars for the first time on astronomical photos of M31. These were made using the 2.
Polaris is also notable for being a Cepheid variable, a pulsating variable star with precise periods of luminosity and pulsation, useful for measuring distances between celestial objects.
Polaris is a blue-green Cepheid variable star (its size brightness changes periodically, with period of 3.969778 days; it varyies between mag 1.92 and 2.07). Polaris has a relatively dim companion star (9th magnitude).
Delta Cephei,is a prototype for what are now called Cepheid variable stars. The study of stars such as these helps astronomers determine distance.
On the scale of largest-known stars, Cepheus boasts three in the top five! ...
Some stars are intrinsically variable; that is, the variability is due to internal causes rather than external ones. The cepheid variables are members of a very important class of variables.
A relationship that describes how the luminosity or absolute brightness of a Cepheid variable star depends on the period of time over which that brightness varies.
Photometer ...
Henrietta Swan Leavitt discovers Cepheid variables.
1911-14 A.D.
Denmark, U.S.A.
Cepheids and RR Lyrae Stars.
Figure 3. Light variation of a Cepheid variable. It is plotted so that two cycles of pulsation are shown.
However, it is so much bigger and hotter than Sol that it will exhaust its core hydrogen after only another 650 million years or so (for a total life of around a billion years) and turn into a red giant or Cepheid variable before puffing away its ...
Its most celebrated star is Delta Cephei, a pulsating supergiant star that varies in brightness every 5.4 days. It is the prototype of the Cepheid variable stars that astronomers use for estimating distances in space.
In 1950 Baade had discovered that Hubble's estimate of the distance to the Andromeda Galaxy, 700,000 light years, was half too small, based on the identification of Cepheid variables in Andromeda.
A large eccentricity also produces an unsymmetrical light variation, the minimum occurring at a time not midway between two maxima; stars of this character are called Cepheid variables, after the typical star S Cephei.
 See also: Cepheid, Telescope, Solar, Sky, Planet
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