Variable Star
Related Category: Astronomy: General
star that varies, either periodically or irregularly, in the intensity of the light it emits.
Variable Stars
Despite the apparent constancy of the stars in the night sky, many stars are known to vary in their luminosity or spectral features, with well over 30,000 variable stars having now been catalogued.
Variable star designation
Variable stars are named using a variation on the Bayer designation format of an identifying label (as described below) combined with the Latin genitive of the name of the constellation in which the star lies.
variable star
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Posted: 23 April 2011 ...
Naming variable stars
Variable star names are descended from an old naming system for bright stars within constellations.
Variable Stars :
Variable stars are any star whose observed light varies notably in intensity. The changes in brightness may be periodic, semiregular, or completely irregular.
Variable Stars
AAVSO: American Association of Variable Star Observers is an excellent site with a wealth of information and data on variable stars and eclipsing binaries.
Variable star
Wikipedia, the free encyclopedia - Cite This Source
A variable star is a star that undergoes significant variation in its luminosity.
Cepheid Variable Stars
Cepheid variable stars are stars that periodically pulsate because of an instability in their internal structure.
Variable Stars
A variable star gets its name because it can change in size, which we on Earth observe as a change in brightness. When the star is as its smallest, it is brightest, and when it is at its largest, it is at its dimmest.
VARIABLE STAR - Star whose luminosity varies over time. Broadly speaking, variable stars are of two types: (1) stars that are intrinsically variable, that is, their luminosity actually changes, ...
Variable stars
A small number of stars change noticeably in brightness over a relatively short period, and these are known as variable stars. They come in two types.
Variable stars:
There are no variable stars of interest to the amateur astronomer.
Deep Sky Objects:
NGC 3115 is a bright galaxy seen edge-on, looking like a fuzzy flying saucer. It may be over 20 million light years away.
variable star A star whose luminosity changes with time.
vernal equinox Date on which the Sun crosses the celestial equator moving northward, occurring on or near March 21.
VARIABLE STAR
A variable star is one whose brightness changes regularly. They can have periods ranging from minutes to years.
Variable Star
(a) A star whose luminosity changes over periods of time; there are many reasons and many types. Periods vary widely in length and even regularity. Novae and supernovae are classed as variables.
Variable Stars on the HR Diagram
While most of the main sequence is stable, many other regions of the HR diagram (including a section of the main sequence itself) are not.
Variable Stars
All stars probably vary slightly in their brightness on a more or less periodic basis, including the sun. Such variations may be scarcely measurable. Some stars, however, change greatly in brightness and are called variable stars.
Variable Star: A star that changes its brightness. There are several classes of variable stars, ...
Variable star designations:
DAV or ZZ Ceti: a hydrogen-rich pulsating white dwarf.[48], pp. 891, 895
DBV or V777 Her: a helium-rich pulsating white dwarf.[49], p. 3525 ...
Variable Star
A star whose brightness changes periodically.
Velocity ...
Variable stars. A star that varies in brightness over a period of time. There are many types of variable stars, some vary over hundreds of days while other display minute variation over a matter of minutes.
Variable Star
a star that fluctuates in brightness. These include eclipsing binaries.
Vent
the opening in the crust through which volcanic material erupts.
Helium Variable Stars
Bp stars in which the strength of the helium lines varies periodically. At the extreme phases the objects appear as helium-rich, whereas at other phases He can be very weak or absent.
Helix Nebula ...
Nebular Variable Stars
Also called T Tauri variables, a type of variable star of spectral classification F, ...
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.
MIRA VARIABLE STAR
A Mira variable star is a variable star whose brightness and size cycle over a very long time period, in the order of many months.
Variable Stars. - Although the majority of the stars are unchanging in magnitude, there are many exceptions. Stars whose brightness fluctuates are called variable stars.
Variable Stars
Classical Nova
Classical novae (CN) are a class of nova and cataclysmic variable that have only a single observed eruption. Typical brightness ranges for CN range from 6 to greater than 19 magnitudes.
Variable stars L2 Pup, V Pup, h1 Pup
Double stars xi Pup, sigma Pup, k Pup, n Pup
Star cluster M 46, M 47, M 93, NGC 2439, NGC 2451, NGC 2477, NGC 2546, NGC 2567, NGC 2571
Planetary nebulae NGC 2438, NGC 2440
Meteor shower: Alpha Puppids ...
Variable star with a period of 60 days whose period of variation is related to its luminosity. Collectively, all such stars with similar spectra and period/luminosity realtionships.
charge-coupled device (CCD) ...
variable star A star whose luminosity changes with time. [More Info]
visible spectrum The small range of the electromagnetic spectrum that human eyes perceive as light.
Variable stars
instability strip on H$-$R diagram
stellar pulsation, periods $1-90$ days
RR Lyrae (fainter, lower mass)
Cepheids (brighter, higher mass)
period$-$luminosity relation
distance estimates ...
A variable star that scientists can use to determine how distant a galaxy, or star cluster is.
Charge-Coupled Device (CCD)
A sensitive imaging device which is replacing photography in most branches of Astronomy.
A variable star with a period ranging from 100 days to over 400 days.
Look Back Time The amount by which we look into the past when we look at a distant galaxy; a time equal to the distance to the galaxy in light-years.
Normal variable stars (stars near the end of their life in stages 5 to 7) oscillate brightness by changing their size and temperature.
Famous variable star. Its brightness is 4 times greater at its maximum than at its minimum.
Type of Star:
Red Giant (M2 Ia Spectral Class) ...
Cepheid variable stars have masses between five and twenty times the mass of our Sun. The more massive stars are more luminous and have more extended envelopes (the outer layers of gas in a star are sometimes called its "envelope").
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 VARIABLE STARS
Cepheid variables are supergiant stars that regularly pulsate in size and change in brightness. As the star increases in size, its brightness decreases; then, the reverse occurs. The luminosity is proportional to the period.
Caph is a variable star of Delta Scuti type as well. The brightness fluctuates by about 0.03 magnitudes with a period of 2.4 hours. See Burnham for a detail discussion of the Delta Scuti stars.
Other Designations For This Star
Flamsteed ...
Mira A variable star in the constellation of Cetus, with a range in brightness from 2nd to 10th magnitude, and a mean period of 331 days. Known as Mira the Wonderful, it is the brightest and most famous of the long period pulsating variables.
intrinsic variable star
A star whose apparent brightness will vary with respect to time.
ion
A small particle which has a magnetic charge.
Double Stars, Variable Stars, Clusters and Nebulae
Our Sun is a single star with approximately constant brightness. In fact, in the universe, many stars are not alone, they interact with each other to form binary or multiple star systems.
A New Suspected Variable star designated NSV 161, Beta Hydri is also unusually bright for its spectral type.
[3.3] PULSATING VARIABLE STARS
[4.0] Stellar Mechanics & Evolution (2)
[4.1] TYPE II SUPERNOVAS / SUPERNOVA 1987A ...
It is a suspected variable star and has been categorized under many names:TYC6977:1267:1 HR8728, Hip113368, HD216956, SAO191524, and LTT9292, just to name a few.
There is a bluish variable star "Auriga AE" with 6th magnitude at the center of IC405, known as "Runaway Star". The variable has born in The Great Orion Nebula (M42) and jumped from the nebula.
Cepheid (High Energy Astrophysics Dictionary- GSFC) A pulsating variable star. This type of star undergoes a rhythmic pulsation as indicated by its regular pattern of changing brightness as a function of time.
In particular he was using variable stars to measure distances to globular clusters. Variable stars are stars whose luminosity varies with time as the star pulsates. In particular there is a class of variable star known as Cepheid Variables.
1784 - Edward Piggot discovers the first Cepheid variable star
1838 - Thomas Henderson, Friedrich Struve, and Friedrich Bessel measure stellar parallaxes ...
Along the way I'll introduce you to Mira - a variable star that is a real treat for amateur astronomers.
The Extreme Southern Celestial Hemisphere (Check the study guide for this lesson) ...
You'll notice that both types of clusters have variable stars in them. Clusters can have either Cepheids or RR Lyrae in them, so we can determine the distances to them. How does this help?
1 hours, was discovered by Max Wolf in 1923, then listed in the General Catalogue of Variable Stars as an irregular variable with a range from 12th to 14th magnitude.
[2480] omicron Ceti or Mira was the first variable star to be found in the night sky. It is a red giant approximately 420 light-years distant from Earth. Its maximum magnitude can reach 2.
BL Lac objects were in some cases first catalogued as variable stars (BL Lacertae, AP Librae). They are highly variable, highly polarized, and show virtually featureless continuous spectra.
Binary stars Observing Variable stars Variables are those stars which show some degree of variability in their luminosity and magnitude.Sometimes, the degree of variability may be high.
American Association of Variable Star Observers
American Astronomical Society
The American Meteor Society
British Astronomical Association
Centre de Données astronomiques de Strasbourg
H.M. Nautical Almanac Office ...
Delta (δ) Cephei is the prototype for an intrinsically bright class of regularly pulsating variable stars whose period of variability is closely related to their absolute magnitudes.
 See also: Star, Light, Sky, Constellation, Period
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