3 HR 4330

Winzer (1974) found that HR 4330 (= HD 96707 = EP UMa) (v sin i = 33 km s^-1, Abt & Morrell 1995) was a small amplitude light variable with a possible period of 0.8183 days. Its largest amplitude was in V. Burke & Barr (1981) also observed this star, but one of their comparison stars was unfortunately variable. Matthews & Wehlau (1985) did not find HR 4330 to be a rapid variable. According to Leroy (1995), it should show significant polarization, but does not. We obtained 101 sets of differential uvby observations of which 35 were from 1995-96, 37 from 1996-97, and 29 from 1997-98. Our periodograms indicated that the most likely period was near 3.516 days. We kept the zero point of Winzer's ephemeris and used

HJD($V_{\max}$) = 2441447.19 + (3.5160 $\pm$ 0.0001) E.

The scatter seen in these light curves (Fig. 2) is greater than that for other mCP stars since these check and comparison stars are not as constant as those used with most mCP stars (Adelman et al. 1998). Hence HR 4330 should be reobserved with less variable check and comparison stars. Light maximum apparently comes near phase 0.9 rather than 0.0 as intended, but the shape of the maximum needs to be better defined. The amplitudes of HR 4330 are 0.02 mag in b and 0.025 mag in y with those for u and v probably smaller. The b and y curves are in phase. The v values show scatter while those for u suggest incipient structure.

  

Figure 2: Photometry of HR 4330 plotted using the ephemeris HJD(y$_{\max}$) = 2441447.19 + 3.5160 E. The FCAPT uvby values are indicated by + signs while Winzer's V values as rezeroed to the y scale are closed circles