Z Camelopardalis

Z Camelopardalis (Z Cam) is a cataclysmic variable star system in the northern constellation of Camelopardalis. It has an apparent visual magnitude which varies between 9.8 and 14.5. This system is the prototype star for the family of Z Camelopardalis variable stars: dwarf novae with standstills at a brightness intermediate between their maxima and minima.^[3] It may have been the "guest star" that was recorded by Chinese astrologers in the autumn of 77 BCE,^[6] but a 2024 study argues that this guest star was likely a comet, while one observed in 369 CE may have been Z Camelopardalis.^[7]

Z Camelopardalis

A visual band light curve for Z Camelopardalis, plotted from AAVSO data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Camelopardalis
Right ascension	08h 25m 13.199s[2]
Declination	+73° 06′ 39.28″[2]
Apparent magnitude (V)	9.8 to 14.5[3]
Characteristics
Spectral type	pec(UG)+G1[3]
Variable type	UGZ[3]
Astrometry
Radial velocity (Rv)	−38.0[4] km/s
Proper motion (μ)	RA: −9.003[2] mas/yr Dec.: −19.078[2] mas/yr
Parallax (π)	4.4369±0.0403 mas[2]
Distance	735 ± 7 ly (225 ± 2 pc)
Other designations
Z Cam, 2MASS J08251318+7306391, AAVSO 0814+73[5]
Database references
SIMBAD	data

Z Camelopardalis was discovered photographically in 1904 by Henry Park Hollis during work for the Astrographic Catalogue.^[8] It is surrounded by an extensive shell thought to have been ejected in a nova explosion,^[9] 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.^[6]

Gallery

• 
  Z Camelopardalis light curve showing a characteristic standstill interrupting the otherwise regular eruptions
• 
  Gas shell Around Z Camelopardalis
• 
  Z Camelopardalis in ultraviolet