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Figure 1: New high-precision photometry of PW And in 2004. a) Periodogram from the combined V and y data. The x-axis is in units of cycles per day. b) V (pluses) and y (dots) photometry. The x-axis is in fractional days from JD 2 453 000. c) Phased light and color curves with the ephemeris in Eq. (1). Note that the b-y curve is differential with respect to HD 1440. The spectroscopic observations were obtained during the interval 2 453 243-50. |
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Figure 2:
A lithium spectrum of PW And at R=120 000 ( top). The
Li I 670.8 nm line is the strong line in the center. Its
equivalent width is 278 mÅ corrected for the contribution from an
inactive star ![]() ![]() |
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Figure 3:
Averaged Doppler image of PW And for August 26-31, 2004
(JD 2 453 243-249). Maps are plotted in a spherical projection at
eight equidistant rotational phases. The temperature scale is
indicated and is the same for all projections. The image is an
average from seven spectral regions, see text. Note that the
photospheric temperature is ![]() |
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Figure 4: Doppler image of PW And from the full-spectrum approach. Otherwise as in Fig. 3. |
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Figure 5:
Example line-profile fits. Shown is only the
(simultaneous) inversion of the Fe I 642.1 and Fe I 641.9 line pair for all 27 phases. Phase is indicated in degrees
(0-360![]() |
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Figure 6:
Latitudinally averaged surface temperatures. Shown is
the average temperature per 5-degree latitude bin between the
surface visibility limit at
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Figure 7:
The expected latitude distribution of emerging flux
tubes for PW And. Shown is as a radial cross section with the
trajectories of the summit of rising flux loops (lines; left panel).
Its surfacing probability as a function of latitude between zero and
90![]() ![]() |
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Figure A.1:
Fe I 639.3-nm line profile data and fits for all
27 phases. Phase is indicated in degrees (0-360![]() |
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Figure A.2:
Fe I 640.8-nm line profile data and fits for all
27 phases. Phase is indicated in degrees (0-360![]() |
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Figure A.3:
Fe I 641.1-nm line profile data and fits for all
27 phases. Phase is indicated in degrees (0-360![]() |
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Figure A.4:
Fe I 643.0-nm line profile data and fits for all
27 phases. Phase is indicated in degrees (0-360![]() |
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Figure A.5:
Ca I 643.9-nm line profile data and fits for all
27 phases. Phase is indicated in degrees (0-360![]() |