Standard candles are objects of a given class (e.g., certain types of stars, , etc.) whose distance is computed by comparing the observed brightness to an assumed absolute luminosity.
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Standard Candles
The term standard candle applies to celestial objects with well-defined absolute magnitudes which are assumed to not vary with age or distance. Type I and II Cepheids and RR Lyraes are all examples.
standard candle
an astronomical object of known luminosity; can be used to determine distances
star ...
standard candle Any object with an easily recognizable appearance and known luminosity, which can be used in estimating distances.
Standard Candles
Obtaining distances from the HR diagram is done by using the diagram to obtain the actual luminosity of a star and then comparing that information to the apparent brightness of the star in the sky.
STANDARD CANDLE - Astronomical object with a known absolute magnitude. They are extremely important to astronomers since by measuring the apparent magnitude of the object we can determine its distance.
standard candle
An object for which the absolute brightness can be determined and then used to determine distance.
star
A massive ball of gas which produces its own energy by means of nuclear fusion occurring within its core.
standard candle: Object of known brightness which astronomers use to find distance - for example, Cepheid variable stars and supernovae.
Standard Candle
An object - usually a star or a galaxy of known intrinsic brightness. Measuring the apparent brightness of a standard candle yields its distance.
Standard Deviation () ...
Standard Candles
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Standard candles and the Tully"Fisher relation share the fifth rung of our cosmic distance ladder (Figure 24.12). Just as with the lower rungs, we calibrate the properties of these new techniques using distances measured by more local means.
standard candle - (n.)
A general term for any astronomical object whose absolute magnitude can be inferred from its other observed characteristics, and which is therefore useful as a distance indicator.
star - (n.) ...
Standard Candle
An object whose properties allow us to measure large distances through space. The absolute brightness of a standard candle can be determined without a measurement of its apparent brightness.
standard candle
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The standard candle of choice in cosmological studies is the type 1a supernova. It is as bright as any event in the universe, so it can be seen in the most distant galaxies.
standard candle luminous objects of a known luminosity used to measure large distances via the inverse square law of light brightness.
The similarity in the shapes of the luminosity profiles of all known Type Ia supernovae has led to their use as a standard candle in extragalactic astronomy. The cause of this similarity in the luminosity curve is still an open question.
It is necessary to find standard candles: objects for which the actual brightness, what astronomers call the absolute magnitude, is known, so that it is possible to relate the observed brightness, or apparent magnitude, to the distance.
Such a star is termed a "standard candle." The distance to a standard candle can be calculated from its known luminosity and its measured intensity.
Enormous effort has gone into the determination of H0 and q0 via "classical" tests using galaxies as standard candles. Measurement of H0 has been discussed in the distance-scale lecture.
In the figure above, we take the abundance of silicon as a "standard candle" or reference point, and compare the relative abundances (relative to silicon) of the elements in the solar system and in galactic cosmic rays.
Originally thought to be standard candles where every SNIa had the same peak brightness, it has been shown that this is close to the truth, but not quite. SNIa exhibit brightnesses at maximum that range from about +1.5 to -1.
Sandage, working at the Carnegie Observatories in California, continued his efforts to hone the Hubble Constant, in his latter years using the Hubble Space Telescope to observe extragalactic Type Ia supernovae as standard candles.
Usually, astronomers use standard candles: objects for which the intrinsic brightness, the absolute magnitude, is known. This allows the object's distance to be measured from its actual observed brightness, or apparent magnitude.
Astronomers then turn to a series of methods that use "standard candles", that is, objects whose absolute magnitude is thought to be very well known.
(a) Any distance to a celestial object which has been calculated using a standard candle. [C97] ...
The energy output of this explosion is so well known that it can be used as a standard candle for measuring vast astronomical distances.
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) ...
In 2002 however, the Hubble Space Telescope was used to determine the distance to Delta Cephei (and RR Lyrae, another standard candle) within ~4%: 273 parsecs, or 890 light-years.[3] There is a 7.
Despite significant operational problems, it revised the Cepheid variable star distance scale to great accuracy and has been invaluable for all branches of observational astronomy by furnishing scientists with extremely accurate "standard candles" ...
Of supreme importance, the visual luminosities of Cepheids are tightly correlated with their periods, which makes them wonderful "standard candles" for measuring distances to other galaxies.
In this way Cepheid variable stars can be used as one of the 'standard candles' in the Universe that act either as distance indicators themselves or can be used to calibrate (or set the zero point for) other distance indicators.
 See also: Distance, Galaxies, Light, Galaxy, Star
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