Z Camelopardalis (Z Cam) is a
cataclysmic variable star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
system in the northern
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 first constellati ...
of
Camelopardalis
Camelopardalis is a large but faint constellation of the northern sky representing a giraffe. The constellation was introduced in 1612 or 1613 by Petrus Plancius. Some older astronomy books give Camelopardalus or Camelopardus as alternative form ...
. It has an
apparent visual magnitude
Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...
which varies between 9.8 and 14.5. This system is the prototype star for the family of
Z Camelopardalis variable stars:
dwarf nova
A dwarf nova (pl. wiktionary:nova, novae), or U Geminorum variable, is one of several types of cataclysmic variable star, consisting of a close binary star system in which one of the components is a white dwarf that accretion disk, accretes matter ...
e with standstills at a brightness intermediate between their maxima and minima.
[ It may have been the " guest star" that was recorded by Chinese astrologers in the autumn of 77 BCE,][ but a 2024 study argues that this guest star was likely a comet, while one observed in 369 CE may have been Z Camelopardalis.][ It is surrounded by an extensive shell thought to have been ejected in a ]nova
A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...
explosion,[ the largest known of its type. The size and expansion of this shell sets a firm lower limit since the last eruption of at least 220 years.][
]
Gallery
File:Z Camelopardalis light curve.png, Z Camelopardalis light curve
In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...
showing a characteristic standstill interrupting the otherwise regular eruptions
File:Gas Shell Around Z Cam.jpg, Gas shell Around Z Camelopardalis
File:Z Camelopardalis GALEX.jpg, Z Camelopardalis in ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...
References
External links
*
G-type main-sequence stars
Dwarf novae
Camelopardalis
Camelopardalis, Z
J08251318+7306391
{{var-star-stub