3 19 Lyr

Winzer (1974) discovered the light variations of 19 Lyr (= HR 7283 = HD 179527 = V471 Lyrae) of 0.04 mag in U with smaller B and V amplitudes. His tentative period of 1.1608 days was based upon very limited data. Burke & Barr (1981) obtained additional UBV photometry and confirmed Winzer's period.

We obtained differential uvby observations of 19 Lyr: 18 in the 1995-96 observing season, 40 in 1996-97, and 66 in 1997-98. The periodogram contains several possible periods of which one near 7.10 days, which is an alias of Winzer's period, is the most likely and consistent with the v sin i value of Abt & Morrell (1995), 20 km s^-1. Using the V data of Winzer and of Burke & Barr, we refined the period. Winzer's zero epoch appeared to be satisfactory. Thus

HJD (light maximum) = 2441449.99 $\pm$ 0.01 + (7.0980 $\pm$ 0.0001) E.

Figure 2 shows the FCAPT values as + signs and Winzer's and Burke & Barr's V data rezeroed to our y scale as solid diamonds and circles, respectively. The variations in u, v, b, and y are in phase. The curves suggest possible incipient structure. The amplitudes are 0.045 mag, 0.025 mag, 0.030 mag, and 0.025 mag for u, v, b, and y, respectively. There is a sharp primary maximum with a weaker secondary maximum whose prominence decreases with increasing wavelength. Two approximately equal strength minima are symmetrically located with respect to the secondary maximum.

  

Figure 2: Photometry for 19 Lyr using the ephemeris HJD (light maximum) = 2441449.99 + 7.0980 E. The FCAPT uvby values are indicated by + signs while the V values of Winzer and Burke & Barr rezeroed to the FCAPT y scale are shown, respectively, as closed diamonds and circles