Science help?

Question

1.What is a pulsating variable star?
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2.What type of star beams radiaton through space like a searchlight?
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3.What does an H-R diagram show a realtionship between?

help would be nice.

Answer 1

1) A pulsating variable is one that has a cycling variation in intensity.:

From wikipedia http://en.wikipedia.org/wiki/Variable_star

"The majority of pulsating stars periodically swell and shrink. The two most important types are:

* Cepheids and cepheidlike stars. They have short periods (days to months) and their luminosity cycle is very regular;
* Long Period Variables. Their period is longer, on the order of a year, and much less regular.

A small number of stars are nonradial pulsators: the total volume of the star remains the same, but the shape of the star oscillates."

2) Pulsars, a type of neutron star. See http://en.wikipedia.org/wiki/Neutron_stars

3)H-R diagram plots star luminosity against color. Sehttp://en.wikipedia.org/wiki/H-R_diagram