Which stars have the shortest period of variability?

We present the discovery of a 3h5m orbital-period binary star at the heart of the planetary nebula M 3-1 – the shortest period photometrically-variable central star known and second only to V458 Vul, in general.

What is the period of a Cepheid variable star?

3.7 days
A Cepheid variable star has a period of 3.7 days, and from this we know its absolute magnitude is -3.1. Its apparent magnitude is 5.5.

What are the types of variable stars?

There are two basic types of variable stars: intrinsic variables, whose luminosity actually changes, and extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth. A star could be an intrinsic variable because it periodically swells and shrinks.

What type of star is a Cepheid variable?

A Cepheid variable (/ˈsɛfiːɪd, ˈsiːfiːɪd/) is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.

What is a variable star?

variable star, any star whose observed light varies notably in intensity. The changes in brightness may be periodic, semiregular, or completely irregular. For full treatment, see star: Variable stars.

Is a supernova a variable star?

Supernovae are the most dramatic type of cataclysmic variable, being some of the most energetic events in the universe. A supernova can briefly emit as much energy as an entire galaxy, brightening by more than 20 magnitudes (over one hundred million times brighter).

Which shows the smallest parallax shift?

The nearest star has a distance of 4.2 light years, which is 1.3 pc. Its parallax angle is 0.77″ — small! Stars are so distant that measuring parallax is difficult. The smallest parallax angles which are currently measurable are about 0.001″, corresponding to a distance of 1000 parsecs (a kiloparsec).

What is the period luminosity relation for variable stars?

In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables, sometimes called the Leavitt law.

Is a binary star a variable star?

Eclipsing binaries are variable stars, not because the light of the individual components vary but because of the eclipses. The light curve of an eclipsing binary is characterized by periods of practically constant light, with periodic drops in intensity when one star passes in front of the other.

What are the two types of variables?

You can think of independent and dependent variables in terms of cause and effect: an independent variable is the variable you think is the cause, while a dependent variable is the effect.

What is the period-luminosity relation for variable stars?

How many Cepheid variable stars are there?

More than 400 Cepheids are known in the Galaxy and about 1000 Cepheids have been found in each of the two nearest galaxies, the Magellanic Clouds, as well as substantial numbers in other nearby galaxies. The close relationship between period and luminosity which was found by Henrietta S.

What determines the period of a pulsating variable star?

Pulsating variable stars. Depending on the type of pulsation and its location within the star, there is a natural or fundamental frequency which determines the period of the star. Stars may also pulsate in a harmonic or overtone which is a higher frequency, corresponding to a shorter period.

What causes the variation in the luminosity of a star?

This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either: Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.

What are the different types of variable stars in the universe?

Cataclysmic or explosive variables, stars that undergo a cataclysmic change in their properties like novae and supernovae. Extrinsic variable stars: stars where the variability is caused by external properties like rotation or eclipses. There are two main subgroups.

What is the average period of a binary star?

The periods are typically short and range between 0.25 days to around 1.0 days. Each of the components in the binary are of nearly the same spectral type, from around middle A to early K, with the bulk concentrated in middle F through early G. The stars are assumed to be in a similar evolutionary state, located near or just above the main sequence.