QX Andromedae (often abbreviated to QX And) is an

eclipsing binary A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Andromeda. It varies from a maximum

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 11.28 to a minimum of 11.50. Since it is impossible to specify the onset time of the eclipses, it is classified as a

W Ursae Majoris variable A W Ursae Majoris variable, also known as a low mass contact binary, is a type of eclipsing binary variable star. These stars are close binaries of spectral types F, G, or K that share a common envelope of material and are thus in contact with one ...

star. It is also observed as an

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

source and is a member of the

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

NGC 752 NGC 752 (also known as Caldwell 28) is an open cluster in the constellation Andromeda (constellation), Andromeda. The cluster was discovered by Caroline Herschel in 1783 and cataloged by her brother William Herschel in 1786, although an object th ...

System

As a whole, the QX Andromedae system emits light like a stellar

blackbody A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. The name "black body" is given because it absorbs all colors of light. A black body ...

, with a F6

spectral type In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

. The two stars in the system complete an orbit every 9.892 hours; they are so close that their envelopes are touching each other. Their temperature is similar, but they have different radius and mass. Since they belong to an open cluster, the age of this system is equal to the cluster estimated age ( billion years).

Variability

The

light curve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

of QX Andromedae shows almost equal eclipses; the primary eclipse occurs when the less massive star pass in front of the other one. The brightness variations are rather small for this system given the low orbital inclination of 55°.

References

{{DEFAULTSORT:QX Andromedae Andromeda (constellation) Andromedae, QX J01575777+3748224 W Ursae Majoris variables Eclipsing binaries