Zeta Chamaeleontis
Variable star in the constellation Chamaeleon
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Zeta Chamaeleontis is a binary star system located in the constellation Chamaeleon. Its name is a Bayer designation that is Latinized from ζ Chamaeleontis, and abbreviated Zet Cha or ζ Cha. This is a 5th magnitude star, faintly visible to the naked eye under good observing conditions. Based on parallax measurements, it is located around 540 light-years distant.
  | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Chamaeleon[1] |
| Right ascension | 09h 33m 53.37537s[2] |
| Declination | −80° 56′ 28.5287″[2] |
| Apparent magnitude (V) | 5.07[1] (5.06 - 5.17)[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | B5V[1] |
| Variable type | eclipsing[4]+ELL[5] |
| Astrometry | |
| Radial velocity (Rv) | −42.0±4.2 km/s |
| Proper motion (μ) | RA: −34.582 mas/yr[2] Dec.: +13.564 mas/yr[2] |
| Parallax (π) | 6.0043±0.1134 mas[2] |
| Distance | 540 ± 10 ly (167 ± 3 pc) |
| Absolute magnitude (MV) | −1.15[1] |
| 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[12] | |
| Database references | |
| SIMBAD | data |
South African Astronomer A.W.J. Cousins noted ζ Cha to vary between magnitudes 5.06 and 5.17 in 1960.[14] It was classified as a Beta Cephei variable in the Hipparcos and Tycho Catalogues (ESA 1997), with a period of 1.07 days,[15] before being reclassified as a slowly pulsating B star in the 2011 version.[16] 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]
This is classified as a B5V main sequence, 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. It shines with a luminosity approximately 522 times that of the Sun and has an effective temperature of 15,655 K.