Do metal-polluted stars of the ZZ ceti instability strip have a distinct asteroseismic signature?
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Cooling DA stars that pass through the ZZ instability strip, a region between temperatures of approximately 12,600 K to 11,100 K, tend to experience the driving of g-mode pulsations near their surface layers. These pulsations cause variations in the luminosities of such stars, leading them to be known as DAVs. A fraction of DAVs also have photospheres contaminated by metals, usually thought to be from the tidally disrupted remnants of planetary systems. The high resolution spectroscopy needed to make definite identifications of these metal lines is relatively demanding, whereas it is simple to obtain photometric data on the pulsation periods of DAV stars. Therefore, if known metal-polluted DAVs (DAZVs) have systematic differences in their photometric data compared to that of DAVs that lack such pollution, photometry could provide an easy way to determine which stars are likely to contain metals in their photospheres in the future. However, we find that the known DAZV population is not large enough to permit its behavior to be distinguished from that of the normal DAV population at the present time, though extremely low-mass white dwarfs may help expand the populations and improve the quality of our fits.