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Astron. Astrophys. 355, L35-L38 (2000)

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3. Results: [FORMULA] Scuti candidates

The stars V346 Ori, V351 Ori, BF Ori, HD 35929, and AK Sco have been found to show photometric variability. For V351 Ori and HD 35929, we could derive reliable pulsational periods that fall in the expected range of [FORMULA] Scuti type variability 1. In Table 1 we report their main properties.


[TABLE]

Table 1. Herbig Ae stars with [FORMULA] Scuti type variability.
Notes:
a) van den Acker et al. (1998);
b) main pulsation period


HD 35929 was observed during two nights (Dec. 28 and 29, 1998). The stars HD 37399 and HD 37210 were used for comparison. Unfortunately, HD 37210 turned out to be variable with a maximum amplitude in the u-filter of [FORMULA]0.03 mag and a rather monotonic variation. Therefore, the differential light curve of HD 35929 was derived using the data points relative to HD 37399 only. The instrumental phased light curves in [FORMULA] and [FORMULA] are shown in the two upper panels of Fig. 1. The frequency spectrum of HD 35929 obtained from the u-filter is shown in the lower panel of Fig. 1. The frequency spectrum peaks at 5.1 d-1, i.e. 0.196d. We note that no significant differences in the calculated period are found using light curves in other filters.

[FIGURE] Fig. 1. Upper panels : differential (variable-comparison star) light curves of HD 35929 in the u- and b-filters. Filled and open circles refer to the first and second night of observation respectively. Lower panel : frequency spectrum of HD 35929.

V351 Ori was observed during the nights of Dec. 23 and 25, 1998. HD 38155 and HD 35298 were used as comparison stars. The latter turned out to be a variable star, with a maximum amplitude in u of [FORMULA]0.04 mag and a quasi-periodic behaviour. Thus, we use only HD 38155 for comparison. The differential magnitudes in each filter ([FORMULA], computed as variable-comparison) are shown in the upper panels of Fig. 2. The light curve in the u-band, where the largest amplitude is observed, was used to determine the observed period of V351 Ori. The frequency spectrum of V351 Ori obtained from the u-filter is shown in the lower panel of Fig. 2. The main maximum in this spectrum corresponds to a period of 0.058 d. Again, no significant differences in the derived periods occur when using light curves in other filters.

[FIGURE] Fig. 2. Upper panels : differential (variable-comparison star) light curves of V351 Ori in the labeled filters for the nights of Dec. 23 (top panel ) and Dec. 25 (middle panel ). Lower panel : frequency spectrum of V351 Ori in the first and second night of observation (solid and dotted lines, respectively). The peak frequency (in days-1) for each night is also indicated.

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© European Southern Observatory (ESO) 2000

Online publication: March 21, 2000
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