In this artist's view, the larger, cooler star in the Algol pair deeply eclipses the smaller, brighter star every 2.9 days. We can easily see the eclipse as a dramatic change in Algol's brightness.

Algol (Beta Persei), the second brightest star in the constellation Perseus, exhibits regular variations in brightness observable without a telescope. This variability is due to a binary star system ...

These photos contrast the star Algol at normal brightness (left) and when it's eclipsed by a close companion star 2.9 days later. Algol is located in the constellation Perseus, which is shaped liked a ...

Binoculars or small telescopes easily show double stars and star clusters. Several planets are visible this week, some with moons or other celestial neighbors. The changing position of planets and the ...

Stars are the fundamental building blocks of our universe. Most stars host planets, like our Sun hosts our solar system, and if you look more broadly, groups of stars make up huge structures such as ...

Binary star systems are not rare. Neither are systems where one star is a remnant like a white dwarf or neutron star, and its ...