Astron. Astrophys. 333, 565-570 (1998)

3. The light curves

Fig. 2 clearly shows the gradual increase in visual magnitude V by about 0:m07 y^-1 with associated reddening in , and (the latter amounting to about 0:m05 y^-1) and cyclic microvariations. The brightening phase is strongly present in y, and decreases towards b and v. Superimposed on these longer-term trends are the microvariations (the so-called  Cygni-type variations near the minimum of the SD cycle, see van Genderen et al. 1997a,b, and the longer [ 100 d] cycles near maximum) and a much slower oscillation about the gradual, brightening trend. The data collected in 1996 show an apparently steep descent in y accompanied by a blueward shift in the colour index. Note that this apparent steep descent could have been enhanced by a coincident descending part of the superimposed variability.

Fig. 2. Differential light curves of R 40 (P minus A) in the instrumental system (). The top panel also contains the Walraven V magnitudes expressed in the Johnson scale. Filled triangles represent the 1995-1996 LTPV data

© European Southern Observatory (ESO) 1998

Online publication: April 20, 1998
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