Zeta Chamaeleontis Explained

Zeta Chamaeleontis, Latinized from ζ Chamaeleontis, is a star located in the constellation Chamaeleon. 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.

South African Astronomer A.W.J. Cousins noted ζ Cha to vary between magnitudes 5.06 and 5.17 in 1960.^[1] It was classified as a Beta Cephei variable in the Hipparcos and Tycho Catalogues (ESA 1997), with a period of 1.07 days,^[2] before being reclassified as a slowly pulsating B star in the 2011 version.^[3] 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.

It is a B5V main sequence star with an effective temperature of, 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.

Notes and References

1. Cousins. A.W.J.. 1960. New Bright Variable Stars. Monthly Notes of the Astronomical Society of Southern Africa. 19. 56. 1960MNSSA..19...56C.
2. Book: ESA. 1997. The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission. Esa Special Publication. 1997ESASP1200.....E . 9290923997. 1200.
3. Dubath, P. . Rimoldini, L. . Süveges, M. . Blomme, J. . López, M. . Sarro, L. M. . De Ridder, J. . Cuypers, J. . Guy, L. . Lecoeur, I. . Nienartowicz, K. . Jan, A. . Beck, M. . Mowlavi, N. . De Cat, P. . Lebzelter, T. . Eyer, L. . 2011. Random forest automated supervised classification of Hipparcos periodic variable stars. Monthly Notices of the Royal Astronomical Society. 414. 3. 2602–17. 10.1111/j.1365-2966.2011.18575.x . 2011MNRAS.414.2602D. 1101.2406 . 118560311 .
4. IJspeert . L. W. . Tkachenko . A. . Johnston . C. . Garcia . S. . De Ridder . J. . Van Reeth . T. . Aerts . C. . An all-sky sample of intermediate- to high-mass OBA-type eclipsing binaries observed by TESS . Astronomy & Astrophysics . August 2021 . 652 . A120 . 10.1051/0004-6361/202141489 . 2107.10005 . 2021A&A...652A.120I . free .