A Cepheid is a member of a class of pulsating variable stars. The relationship between a Cepheid variable's luminosity and pulsation period is quite precise, securing Cepheids as viable standard candles and the foundation of the Extragalactic Distance Scale.
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A Cepheid is a member of a particular class of variable stars. The relationship between a Cepheid variable's luminosity and pulsation period is quite precise, securing classical Cepheids as viable standard candles and the foundation of the Extragalactic Distance Scale. See related link for more information
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A Cepheid variable or a nova depending on what you are trying to observe.
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The apparent brightness of the main star in the system is 1.98 but remember that this is a Cepheid variable.
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The Cepheid phase is a stage in the life cycle of a star where the star pulsates in a predictable manner, changing in brightness over a fixed period of time. This pulsation is used by astronomers to accurately measure the distance to Cepheid variable stars and other celestial objects.
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Henrietta Swan Leavitt discovered the relationship between the period and luminosity of Cepheid variable stars in 1908. This discovery led to the development of a method to accurately measure distances to faraway galaxies, known as the cosmic distance ladder.
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seh-fee-id or see-fee-id (most common pronunciations I think:) 'seh' as in seven or 'see' as in 'sea'
Important variable star for distance calculations.
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Cepheid Variables.
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This is not a scrambled word, just the letter J added to Cepheid Variable (a type of star).
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The main star of the system is Ursa Minor Aa which is a Cepheid Variable. Its apparent magnitude averages at 1.98
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No, not all red giants are Cepheid variables. Cepheid variables are a specific type of variable star that pulsates regularly, making them useful for measuring cosmic distances. Red giants, on the other hand, encompass a broad class of stars in the later stages of their evolution, which may or may not exhibit variability in their brightness.
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RR Lyrae stars.
(Sometimes these stars are classed as a type of "Cepheid variable", but they are usually considered as a separate star type.)
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1)placing cosmological constraints on the expansion of the Universe through the determination of distances to galaxies
2)to measure many characteristics of our galaxy and our relationship to it
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Cepheid variable stars are used in astronomy to measure distances by observing their pulsation periods. The longer the period of pulsation, the brighter the star, allowing astronomers to calculate the star's true brightness and therefore its distance from Earth. This method, known as the period-luminosity relationship, helps determine distances to faraway galaxies and other celestial objects.
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Henrietta Leavitt was famous for her discovery of the relationship between the luminosity and the period of Cepheid variable stars. This discovery allowed astronomers to measure the distance to faraway galaxies and greatly contributed to our understanding of the universe's size and structure.
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As of July 2014, the market cap for CEPHEID (CPHD) is $2,827,322,635.80.
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Henrietta Leavitt discovered a relationship between the luminosity and the period of variability of Cepheid variable stars, known as the period-luminosity relation. This groundbreaking finding allowed astronomers to use Cepheids as "standard candles" for measuring astronomical distances. By knowing the intrinsic brightness of a Cepheid and comparing it to its observed brightness, scientists could determine how far away the star is, significantly advancing the field of astrophysics and our understanding of the universe's scale.
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That is a difference of ten magitudes so the factor in brightness is 10,000.
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Cepheid variables
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seh-fee-id or see-fee-id (most common pronunciations I think:) 'seh' as in seven or 'see' as in 'sea'
Important variable star for distance calculations.
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Henrietta Leavitt studied Cepheid variables, a certain type of variable star with brightness that varies in a very regular cycle.
By studying Cepheid variables in the Magellanic clouds, she discovered a simple relationship between the brightness of a Cepheid variable star and the length of time the cycle takes to repeat itself. To do this she used the fact that all such variables in the clouds are at the same distance from us, approximately.
This allowed her to calculate the absolute magnitude of the star just by measuring the time period of the variation in brightness.
The importance of this technique is that Cepheid variables can be found in more distant galaxies, and this provides a yardstick for finding out how far away they are. All you have to do is find a Cepheid variable in a galaxy and measure its variation period, then you know its absolute magnitude. You already know its apparent magnitude so it becomes possible to calculate how far away it is.
This is one of the methods that astronomers used in the early 20th century to reveal the unexpectedly huge distances of other galaxies in the universe. Let's hear it for Miss Henrietta Leavitt!
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Alpha Lupi is 550 ly from Earth.
It is a giant hot blue star of type B1.5. It has also been classified as a Beta Cepheid Variable.
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Objects with large proper motion tend to be closer than objects with small proper motion. /\
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Edwin Hubble used Cepheid variable stars to measure the distances to galaxies. These stars have a relationship between their luminosity and pulsation period, allowing astronomers to calculate their distance based on their observed brightness.
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The main star in the Polaris system, Polaris Aa, is a yellow super-giant, with a radius which is 46 +/- 3 times that of the sun. Its apparent magnitude is 1.98 but it is a Cepheid variable.
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Variable stars and main sequence stars can have similar brightness. Variable stars, like Cepheid variables, can fluctuate in brightness over time, while main sequence stars maintain a relatively stable brightness due to their fusion processes.
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Edwin Hubble measured the distance to the Andromeda Galaxy using Cepheid variable stars as standard candles. By observing how the brightness of these stars changed over time, he could determine their true brightness and then calculate their distance based on their apparent brightness. This allowed him to estimate the vast distance to the Andromeda Galaxy.
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Cepheid is a company that works to improve healthcare by marketing and manufacturing molecular systems and tests that are not difficult to use. They are working on cancers and infectious diseases in particular.
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The brightness of a Cepheid star is determined by its period-luminosity relationship, which is a relationship between the star's variability period and its intrinsic luminosity. By measuring the period of a Cepheid star, astronomers can use the period-luminosity relationship to calculate its luminosity, and from there determine its apparent brightness as observed from Earth.
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Shapley used the principle that the pulsation period of a Cepheid variable star is directly linked to its intrinsic luminosity. By observing Cepheids in nearby galaxies with known distances, he was able to establish a relationship between the period of pulsation and the luminosity of the star, known as the period-luminosity relationship. This key principle provided a way to accurately measure distances to galaxies and paved the way for understanding the scale of the universe.
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There is no known information about Henrietta Swan Leavitt's favorite book. She was a pioneering astronomer known for her work on variable stars and her discovery of the period-luminosity relation in Cepheid variables, which helped establish the scale of the universe.
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Astronomers use a variety of instruments to measure the distance of stars, including parallax, spectroscopy, and cepheid variable stars. The parallax method involves measuring the slight shift in position of a star when viewed from different locations in Earth's orbit. Spectroscopy analyzes the light emitted by stars to determine their composition and distance. Cepheid variables are stars that pulsate in a regular cycle, allowing astronomers to calculate their distance based on their brightness.
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Henrietta Swan Leavitt was an American astronomer who discovered the relationship between the luminosity and the period of Cepheid variable stars. This discovery provided a way to measure the distances to faraway galaxies and paved the way for important advancements in the field of astronomy.
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The pulsation period of a Cepheid star typically ranges from a few days to a few months. This period is directly related to the star's intrinsic brightness, making Cepheids useful for measuring astronomical distances.
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According to the Wikipedia article, there are different types of Cepheids; really, I think that each type should be investigated separately.For example, classical Cepheids have 4-20 times the mass of our Sun, and such stars are rare - 85-90% of all stars are less massive than our Sun. And not all such stars will automatically be Cepheids at any specific period of time.
I am not sure about the other types of Cepheids - whether they really ARE rare, or if they are, why. In fact, it would seem that nobody knows for sure - according to Wikipedia, article "Type II Cepheid", "The physical properties of all the type II Cepheid variables are very poorly known."
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According to the Wikipedia article, there are different types of Cepheids; really, I think that each type should be investigated separately.For example, classical Cepheids have 4-20 times the mass of our Sun, and such stars are rare - 85-90% of all stars are less massive than our Sun. And not all such stars will automatically be Cepheids at any specific period of time.
I am not sure about the other types of Cepheids - whether they really ARE rare, or if they are, why. In fact, it would seem that nobody knows for sure - according to Wikipedia, article "Type II Cepheid", "The physical properties of all the type II Cepheid variables are very poorly known."
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Cepheid variables are a type of pulsating star whose brightness varies in a regular pattern. The key relationship used in distance measurement is the period-luminosity relation, which states that the longer the pulsation period of a Cepheid, the more luminous it is. By measuring the period of a Cepheid's brightness fluctuations, astronomers can determine its absolute brightness and compare it to its observed brightness to calculate the distance using the inverse square law of light. This method allows for accurate distance measurements to nearby galaxies and helps establish the scale of the universe.
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A pulsating star is a type of variable star that changes in brightness due to periodic expansions and contractions of its outer layers. These changes can be regular or irregular, and the star's size and temperature vary over time. Examples of pulsating stars include Cepheid variables and RR Lyrae stars.
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The North Star, aka Polaris and Alpha Ursae Minoris, is a typical Population I Cepheid Variable star. Its only claim to fame is that it is within half a degree of the celestial north pole, making it a reliable indicator of true north to observors. Further info: http://en.wikipedia.org/wiki/Polaris
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A pulsating variable star brightens and fades in a regular pattern due to periodic changes in its size, temperature, and luminosity. These stars can be categorized into different types, such as Cepheid variables and RR Lyrae stars, based on their specific properties and pulsation periods.
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Henrietta Leavitt made significant contributions to the field of astronomy. She is best known for her work on the relationship between the brightness and the period of Cepheid variable stars, which led to the development of the astronomical distance scale.
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Cepheid variables are high-mass, pulsating variables exhibiting a regular relationship between the period of pulsation and luminosity.
When a star's evolutionary track carries it through a region called the instability strip in the HR diagram, the star becomes unstable and begins to pulsate.
These stars are important to astronomers who study galaxies because Cepheids can be seen at extragalactic distances, and their period or pulsation tells us their luminosities, which in turn tells us their distances.
- Cincinnati
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A cepheid (which take their name from prototypical stars in constellation Cepheus) is a type of star which varies or pulses over time. They are important to astronomy as they help establish a "standard candle" which helps in measurement of distance. The variation in brightness, size and spectrum is proportional to the density and size of the star; thus, the absolute magnitude can be calculated and the distance of a cepheid of a given luminance can be inferred from how quickly it changes. Hubble used this method to show that the "spiral nebulae" were in fact not close objects inside our galaxy but instead were distant galaxies.
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To find the distance to Cepheid variable stars and other pulsating stars, Astronomers find the period-luminosity relation (A relation between the pulsation period of a Cepheid variable and its absolute brightness).
The period-luminosity relationship has been calibrated by many astronomers throughout the twentieth century. A calibration was published by Michael Feast and Robin Catchpole in 1997 using trigonometric parallaxes determined by the Hipparcos satellite. The relationship between a Population I Cepheid's period P, and its luminosity, measured as its mean absolute magnitude Mv was "Mv=-2.81log(P)-(1.43±0.1)" with P measured in days.
The following relations can also be used to calculate the distance d and reddenings E(B − V) to classical Cepheids:
"5log10d=V+(3.43)log10P-(2.58)(V-I)+7.50" "5log10d=V+(4.42)log10P-(3.43)(B-V)+7.15" "E(B-V)=-(0.27)log10P+(0.41)(V-J)-0.26" Where J is on the 2MASS photometric system, and B, I and V represent blue, near infrared, and visual, respectively.
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Cepheid variables are used in astronomy to measure distances to faraway objects. By observing the pulsation period of these stars, astronomers can calculate their intrinsic brightness. By comparing this to their apparent brightness, they can determine how far away the star is, helping to map the vast distances of the universe.
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variable is the variable that variable a variable into a variable. noOb
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