WZ Columbae

Lore & Background

WZ Columbae was identified as a variable star from Hipparcos data and received its variable star designation in 1999. It was initially listed in the General Catalogue of Variable Stars as a slowly pulsating B-type star, but subsequent observations revealed an overabundance of strontium and barium. Combined with Hipparcos photometry, this led to its reclassification as an Alpha2 Canum Venaticorum variable. The star has a stellar classification of B9/9.5 V, indicating it is a main-sequence star with characteristics between B9 and B9.5. It has 3.07 times the mass of the Sun and is estimated to be 394 million years old, having completed 89.2% of its main sequence lifetime. Its luminosity is 124 times that of the Sun. The star appears to be receding from the Solar System, with a heliocentric radial velocity measured. Like most chemically peculiar stars, it has a relatively slow projected rotational velocity.

Reader's Guide

WZ Columbae is notable as a chemically peculiar star of the Alpha2 Canum Venaticorum type, a class of variables that exhibit strong magnetic fields and surface abundance anomalies. Its reclassification from a slowly pulsating B-type star to an Alpha2 CVn variable highlights the importance of detailed spectroscopic and photometric analysis in refining stellar classifications. The star's overabundance of strontium and barium, elements typically enhanced in such stars, provides insight into diffusion processes in stellar atmospheres. The discrepancy between the Hipparcos rotation period of 1.38 days and the TESS data suggesting a period double that value underscores ongoing uncertainties in measuring rotational modulation in these stars. As a relatively bright object at magnitude 5.28, WZ Columbae serves as a useful target for studying chemical peculiarity and magnetic activity in intermediate-mass main-sequence stars. Its location in the southern constellation Columba makes it accessible primarily to observers in the Southern Hemisphere.

Did You Know?

• WZ Columbae was originally classified as a slowly pulsating B-type star before being reclassified as an Alpha2 Canum Venaticorum variable.
• The star is overabundant in strontium and barium, typical of chemically peculiar stars.
• Hipparcos data gave a rotation period of 1.38 days, while TESS data suggests a period double that value.