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Semiregular variable star
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<p>In <a href="/facts/Astronomy/0ArJVM1p">astronomy</a>, a semiregular variable star, a type of <a href="/facts/Variable_star/Ac8mp2gy">variable star</a>, is a <a href="/facts/Red_giant/lla6Bsvy">giant</a> or <a href="/facts/Supergiant/y7w8WEcm">supergiant</a> of intermediate and late (cooler) <a href="/facts/Spectral_type/dYrIuK9H">spectral type</a>. It shows considerable periodicity in its light changes, accompanied or sometimes interrupted by various irregularities. Periods lie in the range from 20 to more than 2000 <a href="/facts/Day/MTAtWLDj">days</a>, while the shapes of the <a href="/facts/Light_curve/zN0wdtaR">light curves</a> may be rather different and variable with each cycle. The amplitudes may be from several hundredths to several <a href="/facts/Apparent_magnitude/7pCTF1Me">magnitudes</a> (usually 1-2 magnitudes in the V filter). </p>