2 HD 15980

Bidelman (1983) discovered HD 15980 to be a magnetic CP star. Intermediate and narrow band photometry by Schneider (1986) indicated that it might be a star with a strong $\lambda$5200 broad, continuum feature or depression and thus a star with a potentially strong magnetic field. Adelman et al. (1998) found that Hipparcos photometry indicated that it was possibly variable and that its check star was slightly less variable than its comparison star.

The FCAPT obtained 13 sets of uvby observations in the 1995-96 observing season, 34 sets in 1996-97, and 48 sets in 1997-98 (Table 3). HD 15980 is best described as almost constant during an observing season (Tables 2 and 3). The Scargle periodograms (Scargle 1982; Horne & Baliunas 1986) do not yield any significant periods. The mean v and y values are constant for the three seasons, but the mean u value has changed by 0.022 mag and the mean b value 0.004 mag between 1995-96 and 1997-98. The change in u in particular suggests that HD 15980 is a long period variable and hence this star should be quite sharp-lined, a prediction which needs to be checked.