What are the three types of variable stars?
A variable star is, quite simply, a star that changes brightness. A star is considered variable if its apparent magnitude (brightness) is altered in any way from our perspective on Earth.
What are the two 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.
Where are variable stars found?
globular clusters
SX Phoenicis variables These stars of spectral type A2 to F5, similar to δ Scuti variables, are found mainly in globular clusters. They exhibit fluctuations in their brightness in the order of 0.7 magnitude (about 100% change in luminosity) or so every 1 to 2 hours.
How are variable stars named?
Variable stars are named by constellation, and in the order that they are identified. The first variable star in a constellation is called R (e.g., R Mon ), the second S, and so on through Z.
What are variable stars used for?
Variable stars play a crucial role in our understanding of the universe. Cepheid variables have played a major part in determining distances to far-away galaxies and determining the age of the Universe. Mira variables give us a glimpse into the future evolution of our own star, the Sun.
What does the period of a variable star mean?
Cepheid variable, one of a class of variable stars whose periods (i.e., the time for one cycle) of variation are closely related to their luminosity and that are therefore useful in measuring interstellar and intergalactic distances.
What are the independent and dependent variables of the HR diagram?
Manipulated (independent) variable of the HR diagram. Also tells color and spectral class. The amount of light a star releases. Responding (dependent) variable of the HR diagram.
Why are T Tauri stars variable?
The random variations (with time-scales from minutes to years) may be caused by instabilities in the accretion disk (which also produce the ‘bullets’ of material seen in the jet of HH-30 above), flares on the stellar surface, or simple obscuration by nearby dust and gas clouds.
Do all stars become T-Tauri?
T-Tauri stars are young stars, not much older than about 10 million years old. Their mass is usually less than three solar masses. Not all stars will become T-Tauri stars, it is possible our star was once a T-Tauri star as it is conceivable that our star was once a T-Tauri star before becoming a Main Sequence star.