Zeta Chamaeleontis

Not to be confused with Z Chamaeleontis.

Zeta Chamaeleontis, Latinized from ζ Chamaeleontis, is a star located in the constellation Chamaeleon. It is a 5th magnitude star, faintly visible to the naked eye under good observing conditions. Located around 540 light-years distant, it shines with a luminosity approximately 522 times that of the Sun and has a surface temperature of 15,655 K.

ζ Chamaeleontis

Location of ζ Chamaeleontis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Chamaeleon
Right ascension	09h 33m 53.37537s[1]
Declination	−80° 56′ 28.5287″[1]
Apparent magnitude (V)	5.07[2] (5.06 - 5.17)[3]
Characteristics
Spectral type	B5V[2]
Variable type	eclipsing[4]+ELL[5]
Astrometry
Radial velocity (Rv)	−42.0±4.2 km/s
Proper motion (μ)	RA: −34.582[1] mas/yr Dec.: +13.564[1] mas/yr
Parallax (π)	6.0043±0.1134 mas[1]
Distance	540 ± 10 ly (167 ± 3 pc)
Absolute magnitude (MV)	−1.15[2]
Details
Mass	3.12[6] M☉
Radius	4.75[7] R☉
Luminosity	522[8] L☉
Surface gravity (log g)	3.55[6] cgs
Temperature	15,655[9] K
Metallicity [Fe/H]	−0.31[6] dex
Rotational velocity (v sin i)	103[10] km/s
Age	184[11] Myr
Other designations
CPD−80°365, HD 83979, HIP 46928, HR 3860, SAO 258538
Database references
SIMBAD	data

Light curve for Zeta Chamaeleontis, plotted from TESS data^[12]

South African Astronomer A.W.J. Cousins noted ζ Cha to vary between magnitudes 5.06 and 5.17 in 1960.^[13] It was classified as a Beta Cephei variable in the Hipparcos and Tycho Catalogues (ESA 1997), with a period of 1.07 days,^[14] before being reclassified as a slowly pulsating B star in the 2011 version.^[15] It is now known to be an eclipsing binary star, with a period of 2.7 days,^[4] with continuous variation through the whole cycle due to the ellipsoidal shape of the component stars.^[5]

It is a B5V main sequence star with an effective temperature of 15,655 K, an absolute magnitude of −1.15 and a mass of 3.1 solar masses, although the properties are evaluated treating the system as a single star.