All Figures

	Figure 1: 3968.5 Å Ca II H absorption line region of the summed CORALIE spectra for HD 73256. A clear emission feature is observed. The dotted line in the center of the line represents the spectrum of a non-active star.
Open with DEXTER


In the text

	Figure 2: Phase-folded radial-velocity measurements obtained with CORALIE for HD 73256 (top). Error bars represent photon-noise errors. The still large residuals around the solution (bottom) show some structure and may be explained by activity-induced jitter (see Sect. 5). For clarity of the diagram, the measurement on JD 2 451 964 is not displayed in the figure.
Open with DEXTER


In the text

Figure 3: SAT differential photometric data ( HD 73256- HD 72673, instrumental system) around the orbital phase of the potential transit (vertical line), in four different colours of the Strömgren photometry, for different nights of observation (different symbols). Typical rms errors of one magnitude difference are 0.003-0.004 (ybv) and 0.005-0.006 (u). The horizontal lines represent the mean magnitude differences (all observations). No indication of a transit is found.

Open with DEXTER


In the text

Figure 4: Top: SAT photometric observations of HD 73256 -  HD 72673 in the y band (instrumental system). The typical uncertainty on is shown in the lower left corner. A periodic structure is clearly appearing in the data. A sine curve with a 13.97-d period (from a Fourier transform) is adjusted to the data and displayed for illustration. Bottom: simultaneous radial-velocity residuals around the best Keplerian solution. A sine curve with the photometric period is also displayed. The phase shift between the two sine curves is 1.53 rad, close to /2, the expected value for spot-induced photometric and radial-velocity variations (Queloz et al. 2001).

Open with DEXTER


In the text

Figure 5: Fourier transforms of radial-velocity residuals around the Keplerian solution ( top), SAT photometric data ( middle), and CCF-BIS measurements ( bottom). Photometric and radial-velocity observations share similar behaviours in the frequency space, whereas no coherence is found in the BIS measurements. The rotation period is found at  = 13.97 days (middle). The vertical arrow on the right hand side in each panel indicates the location of the orbital period.

Open with DEXTER


In the text

	Figure 6: Top: radial velocities (RV, upper panel) and inverse bisector slope (BIS, middle panel) phased with the orbital period (P = 2.5486 d) for HD 73256. Bottom: RV vs. BIS plot (same scale) showing the independence of the two quantities.
Open with DEXTER


In the text

	Figure 7: Same as Fig. 6 but for the residuals around the Keplerian solution, phased with the photometric period (P = 13.97 d).
Open with DEXTER


In the text