Al Kurhah: An Attractive Multiple Star Belonging to a King

The star Xi Cephei, known as Kurhah or Al Kurhah, is a multiple-star system in the constellation Cepheus, the King. While Kurhah may actually be a quadruple star system, most observers will see a pair of stars through backyard telescopes. According to Jim Kaler’s site, the primary star is cooler in temperature (around 7200 K) with an atmosphere of copper, zinc, and rare earth elements. The secondary star, the brightest companion, orbits the primary star every 810 days.

Historically speaking, the Persian astronomer Zakariya al-Qazwini (1203-1283) named the star Al Ḳurḥaḥ (القرحة al-qurhah), an Arabic word translated as a white spot, or blaze, in the face of a horse.¹ Centuries later, the astronomer William Herschel recorded this point of light as a double star on November 5, 1779, remarking it as a fine double star.²

My Observations

This is a pretty double star. I appreciate the primary star’s yellow/orange color against the pale whitish smaller secondary star. Since there are only a handful of faint stars in the near region, the pair seems to float alone in the sky.

Also observed on October 6, 2023, at 9:12 p.m.

Key Stats

Constellation	Cepheus
Best Viewing	Autumn
Visual Magnitude	+6.3 | +4.4
Absolute Visual Magnitude	+3.9
Separation	8.5″ | 272 AU
Position Angle	274°
Distance from Earth	96 ly
Orbital Period	3800 years
Milky Way Location	Orion Spur
My Viewing Grade	A
Designations	SAO 19827, Xi Cep, HIP 108917

Sources and Notes

Banner shared under the Creative Commons Attribution-Share Alike 4.0 International license. Photo by David Ritter. Details here.

¹ Wikimedia Foundation. (2023, August 18). Xi Cephei. Wikipedia. https://en.wikipedia.org/wiki/Xi_Cephei

² MacEvoy, B. (2011). http://www.handprint.com/ASTRO/Herschel_All.html

Sketch by Wayne McGraw