Peremennye Zvezdy (Variable Stars) 43, No. 11, 2023 Received 24 November; accepted 12 December. |
Article in PDF |
DOI: 10.24412/2221-0474-2023-43-121-127
|
Surgut, Russia, e-mail: sav@surgut.ru
I present my discovery and CCD observations of two new small-amplitude Scuti (DSCTC) stars demonstrating multiperiodic pulsations. The paper contains detected frequencies, light curves, finding charts, and other relevant information. |
No. | Star | RA, J2000.0 | Dec, J2000.0 | V |
---|---|---|---|---|
1 | USNO-A2.0 0975-13540472 | |||
2 | USNO-A2.0 1050-12146993 |
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 & 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. For magnitude calibration in
band, we apply data from the Gaia DR3 catalogue. We use single,
relatively bright stars, but with no saturation of pixels for our
CCD camera, without close neighbors, and not demonstrating
brightness variations during the time interval of our
observations. Detailed information about our calibration stars is
collected in Table 2. Uncertainties in the column were
derives from our photometry; Gaia , , and
magnitudes were drawn from the corresponding catalog. Magnitudes
in the Calc. column were obtained using the equation:
(1) |
GSC | σV | Gaia | Calc. V | ||
G | GBP | GRP | |||
01051–01179 | 0.005 | 12.7355 | 12.9894 | 12.3245 | 12.8442 |
01051–01491 | 0.004 | 12.0755 | 12.8689 | 11.2027 | 12.6114 |
01585–00306 | 0.005 | 11.9655 | 12.9243 | 11.0048 | 12.6587 |
01584–00111 | 0.005 | 12.2554 | 12.7376 | 11.6132 | 12.5187 |
01051–01757 | 0.004 | 12.1621 | 12.5855 | 11.5643 | 12.3843 |
01051–00969 | 0.004 | 11.8089 | 12.5785 | 12.5785 | 12.3215 |
To derive periods, we use Period04 software by Lenz & Breger (2005) that implements discrete Fourier transform and is very suitable for analysis of sine-shaped light curves of multiperiodic pulsating variable stars.
Fig. 1. Frequency spectra and light curve of USNO-A2.0 0975-13540472. In the bottom panel, the solid curve is the synthesized light curve and dots are observed data points. |
Observations of this star show rapid variations at a time scale of
about
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). Four
apparently significant frequencies were detected; their parameters
corresponding to the equation:
(2) |
Frequency, c/d | Amplitude, mag | ||
18.52586 | 0.165096 | 0.0092 | |
18.44123 | 0.173702 | 0.0078 | |
16.33431 | 0.080947 | 0.0035 | |
19.50166 | 0.341614 | 0.0012 |
Figure 1 presents the amplitude spectrum of USNO-A2.0 0975-13540472 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. 2.
The -filter phased light curve of USNO-A2.0 0975-13540472 with
the following light elements:
Fig. 4. Frequency spectra and light curve of USNO-A2.0 1050-12146993. In the bottom panel, the solid curve is the synthesized light curve and dots are observed data points. |
Photometric measurements of this star reveal rapid variations at a time scale of about and with a peak-to-peak amplitude about . To search for periodic signals in the observations, we applied Period04 software in the frequency range between 3 and 20 cycles per day that had been selected following recommendations by Breger (2000). Three apparently significant frequencies were detected; their parameters, corresponding to Equation 2 determined by least squares, are collected in Table 4.
Frequency, c/d | Amplitude, mag | ||
9.51668 | 0.235789 | 0.0241 | |
5.65634 | 0.016710 | 0.0096 | |
6.47599 | 0.250858 | 0.0085 |
Figure 4 presents the amplitude spectrum of USNO-A2.0
1050-12146993 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. 5. The -filter phased light curve of
USNO-A2.0 1050-12146993 with the following light elements:
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
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., Skrotkiy, S., Potapov, N., et al. 2023, Transient Discovery Report for 2023-06-23
Sokolovsky, K. V. & Lebedev, A. A., 2018, Astron. and Computing, 22, 28