TW Pictoris is a 14th magnitude

cataclysmic variable In astronomy, cataclysmic variable stars (CVs) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state. They were initially called novae (), since ones with an outburst brightness visible t ...

star system in the southern constellation of

Pictor Pictor is a constellation in the Southern Celestial Hemisphere, located between the star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, and is an abbreviation of the older name Equuleus Pictoris (the "painter's easel ...

. It is located at a distance of approximately 1,430 light-years based on parallax measurements. Photometric observations in the visual band suggest a

binary system A binary system is a system of two astronomical bodies which are close enough that their gravitational attraction causes them to orbit each other around a barycenter ''(also see animated examples)''. More restrictive definitions require that th ...

with an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 6.06 hours. One of the components is an accreting

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes ...

. The X-ray source H0534-581 was identified from the data collected by the HEAO 1 satellite in 1979. In 1984, a candidate optical counterpart was identified by I. R. Tuohy and associates from photographs taken at the Schmidt telescope. A low-resolution spectrum revealed this is a cataclysmic variable, and it was assigned the

variable star designation In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the conste ...

TW Pictoris. It was initially proposed to be an intermediate polar, but the lack of 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 ...

pulsation makes this less likely. The current classification remains controversial.

References

Cataclysmic variable stars Pictor Pictoris, TW {{var-star-stub