HS2201+2610 (hereafter HS2201) is a B~14.3 pulsating sdB star located near the low gravity boundary of the sdBV (=sdB Variable) instability strip, having logg=5.4, Teff=29300 K, log(He/H)=-3.0 by number (Ostensen et al. 2001). Its variability was discovered by Ostensen et al. (2001) and then studied in great detail by Silvotti et al. (2002), showing five close frequencies with periods between 342 and 365 s and amplitudes between 0.3 and 10.2 mma. Although the small number of excited modes renders more difficult the mode identification, which therefore is not univocally determined, on the other hand the relatively simple (and stable in time) spectrum of HS2201 makes it an ideal candidate for trying to measure for the first time the secular variation of the pulsation periods in an sdBV star. More than 190 hours of data over 20 months permit already to obtain an upper limit of 4x10^{-12} for the temporal derivative (Pdot) of the main pulsation period of HS2201. Following current models and depending on the evolutionary status of the star (close to or just after He core exhaustion), a negative Pdot is expected in the range from -1x10^{-13} to -1x10^{-11} (Charpinet et al. 2002), which is not far from the present upper limit. To observe HS2201 as a secondary target during the Xcov23 WET campaign in late August 2003 will significantly reduce the upper limit on Pdot and might even permit to measure for the first time this quantity, which is directly related to the evolutionary modification of the internal structure of the star. Moreover the new data from the WET campaign will also allow to study in more detail the temporal spectrum of this star (new modes might come up) and the amplitude variations of its known pulsation modes.
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