Peremennye Zvezdy (Variable Stars) 43, No. 2, 2023 Received 4 February; accepted 20 February. |
Article in PDF |
DOI: 10.24412/2221-0474-2023-43-14-19
|
Surgut, Russia, e-mail: sav@surgut.ru
I present my discovery and CCD observations of three new small-amplitude Scuti (DSCTC) stars. Two of them demonstrate multiperiodic pulsations. The paper contains detected frequencies, light curves, finding charts, and other relevant information. |
No. | Star | RA, J2000.0 | Dec, J2000.0 | G |
---|---|---|---|---|
1 | USNO-A2.0 1275-14987520 | 1307 | ||
2 | USNO-A2.0 1275-15001392 | 12.82 | ||
3 | USNO-A2.0 1275-15124267 | 13.77 | ||
No. | Telescope | CCD Camera |
|
Frames | Filter |
|
|||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 0.3 m, 1/7.8 | Apogee Alta U9000 | 4958 - 4993 | 630 | unfiltered | 300 | |||||||||||||||
2 | 0.3 m, 1/7.8 | Apogee Alta U9000 | 5315 - 5450 | 719 | 300 | ||||||||||||||||
3 | 0.3 m, 1/7.8 | Apogee Alta U9000 | 6586 - 6604 | 706 | 300 | ||||||||||||||||
4 | 0.25 m, 1/8 | SBIG STXL-6303e | 9841 - 9948 | 667 | 600 | ||||||||||||||||
For basic reductions for dark current, flat fields, and bias, we used IRAF routines and proprietary software TheSkyXTM by Software Bisque Inc. For photometry of new pulsating stars, we applied VaST software by Sokolovsky and Lebedev (2018). All times in this paper are expressed in terrestrial time in accordance with IAU recommendations (resolution B1 XXIII IAU GA), with heliocentric corrections applied. Detailed information about photometrical measurements of each star is given in Table 3.
No. |
|
|
|
|
Filter | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 4958 - 4993 | 459 | 422 | 630 | unfiltered | |||||||||||||||||||||||||
2 | 5315 - 5450 | 190 | 719 | 710 | ||||||||||||||||||||||||||
3 | 6586 - 6606 | 0 | 615 | 706 | ||||||||||||||||||||||||||
4 | 9841 - 9948 | 612 | 626 | 667 | ||||||||||||||||||||||||||
Total | 1261 | 2382 | 2713 | |||||||||||||||||||||||||||
|
To derive periods, we use Period04 software by Lenz and Breger (2005) that implements discrete Fourier transform and is very suitable for analysis of sine-shaped light curves of multiperiodic pulsating variable stars.
Observations of this star show changes in the level of maximum
brightness. To clarify the star's variability features, we
obtained additional observations at the Astrotel Caucasus
observatory and, after its closure, at the Caucasian Mountain
observatory. In total, we collected only 1261 observations between
JD 2454958 and JD 2459948, because this star was outside the field
of view during our observing set No. 3 (see Table 3). All these
observations have sufficient accuracy for period analysis. Using
Period04 software, we derived the following light elements:
Fig. 3. Frequency spectra and light curve of USNO-A2.0 1275-15001392. In the bottom panel, the solid curve is the synthesized light curve and dots are observed data points. |
All four observing sets reveal rapid variations at a time scale of
about
and with a peak-to-peak amplitude about
.
We searched for periodic signals in the observations using
Period04 software in the frequency range between 3 and 20 cycles
per day that was selected following recommendations by Breger
(2000). Two apparently significant frequencies were detected;
their parameters corresponding to the equation
(1) |
Frequency, c/d | Amplitude, mag | ||
---|---|---|---|
8.4137218 | 0.173387 | 0.0128 | |
7.5947267 | 0.947497 | 0.0051 |
Figure 3 presents the amplitude spectrum of USNO-A2.0 1275-15001392 and its theoretical light curve (solid curve) with superposed data points corresponding to individual observations. Light curve variations are easy to notice, they are reproduced with the model rather well. The finding chart based on POSS2 red plate is presented in Fig. 4.
The set of observations obtained for this star demonstrates rapid variations with an amplitude not exceeding . The sufficient number of available measurements and relatively high amplitude made it possible to identify three frequencies, presented in Table 5, with notation corresponding to eq. 1. Fig. 5 presents the amplitude spectrum of USNO-A2.0 1275-15124267 and its theoretical light curve (solid curve) with superposed data points corresponding to individual observations. The finding chart, based on POSS2 red plate, is shown in Fig. 6.
Frequency, c/d | Amplitude, mag | ||
---|---|---|---|
7.3473022 | 0.911653 | 0.0220 | |
7.6409009 | 0.663722 | 0.0208 | |
7.4684716 | 0.187621 | 0.0144 |
Acknowledgements: I would like to thank N.N. Samus for helpful discussion.
References:
Breger, M., 2000, ASP Conference Series, 210, 3
Gaia Collaboration, Vallenari, A., Brown, A. G. A., et al., 2022, ArXiv:2208.00211
Kryachko, T., Samokhvalov, A., Satovskiy, B., Denisenko, D., Peremennye Zvezdy Prilozhenie (Variable Stars Supplement), 2010, 10, No. 10
Lenz, P., Breger, M., 2005, Comm.in Asteroseismology, 146, 53
Shatsky, N., Belinski, A., Dodin, A., et al. 2020, in Ground-Based Astronomy in Russia. 21st Century, ed. I. I. Romanyuk, I. A. Yakunin, A. F. Valeev, & D. O. Kudryavtsev, pp. 127-132
Sokolovsky, K. V., Lebedev, A. A., 2018, Astron. and Computing, 22, 28
Fig. 5. Frequency spectra and light curve of USNO-A2.0 1275-15124267. In the bottom panel, the solid curve is the synthesized light curve and dots are observed data points. |