#spectroscopic binary

Equuleus is a small southern constellation located between the constellations of Aquila, Pegasus and Aquarius.

The brightest star is Kitalpha, a latinised version of the original Arabic name of قطعة الفرس (Qit'a AlFaras or a piece of the horse).

The system is a spectroscopic binary system, in other words, a binary system too close together to visually separate, but that show themselves in the spectrum of light, in this instance one star is a G7III (aging star heading towards the red giant phase) and the other an odd A type star, both greater mass than our own Sun.

The Demon Star (Algol, β-Persei)

Algol is in fact 3 stars, Algol A is a type B star, around 3.6 times more massive than our sun, and is closely orbited by a smaller red star. The red star eclipses the larger star every 2.9 days causing a predictable dimming of the star as it does.

Algol is the most massive star within 100 light years of Earth, and is found in the constellation of Perseus, the A star also pulls gas from the smaller close companion, and periodically creates a Annulus around the star.

It was one of the very first recognised variable stars when British astronomer John Goodricke in 1783 presented a paper to the Royal Society suggesting that something was passing between Earth and the star, or that the star had a dark patch. 

It wasn’t until 1881 that Algol’s periodic dimming was suggested to be a orbiting star, soon followed by evidence of change in the spectrum of light when the dimming occurred, making it the very first spectroscopic binary confirmed.

It was only 30 odd years before this that the very first binary stars had been photographed, and so the notion that a orbiting star could eclipse another in the same system was ground-breaking. 

hair magic!! My best friend is a genius!! @spectroscopic-binary