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Peremennye Zvezdy (Variable Stars) 39, No. 1, 2019 Received 19 August; accepted 6 September.
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Article in PDF |
Photoelectric Observations of 16 Double-Mode
Classical Cepheids
L.N. Berdnikov1, A.Yu. Kniazev1,2,3, A.K. Dambis1, V.V. Kravtsov1
- Sternberg Astronomical Institute, Moscow State University,
Universitetskij pr. 13, Moscow 119992, Russia;
leonid.berdnikov@gmail.com
- South African Astronomical
Observatory, P.O. Box 9, Observatory, Cape Town, 7935 South
Africa
- Southern African Large Telescope Foundation, P.O. Box 9, Observatory, Cape Town, 7935 South Africa
We present 2902 magnitude measurements in the  ,
 , and  filters acquired in 1999-2004 for 16 double-mode
classical Cepheids.
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We performed photoelectric observations of double-mode Cepheids
between March 10, 1999 and April 22, 2004 (JD 2451248-2453118)
with the 0.76-m reflector of the South African Astronomical
Observatory (SAAO), equipped with a pulse-counting photoelectric
photometer. It is a cooled unit that employs a Hamamatsu
photomultiplier in conjunction with filters of the
Kron-Cousins photometric system (Cousins, 1976). A description of
the observing techniques can be found in Berdnikov and Turner
(2004). Observational uncertainties are close to 0.01 mag in all
bands.
We have obtained a total of 2902 measurements for 16 double-mode Cepheids, listed in the Table. The phases of the observations were calculated with the elements from GCVS (Samus et al., 2017) for BE Pup and U TrA; from Antipin (1997) for V458 Sct; from Berdnikov (1992) for AX Vel; and from ASAS-3 (Pojmanski, 2002) for the other stars. The star BE Pup was identified as a double-mode Cepheid by Hacke and Richert (1990); the GCVS considers it a doubtful CWB star. For all the listed Cepheids, with the exception of V1048 Cen, the period in the Table is that of the fundamental mode. V1048 Cen pulsates in the first and second overtones, and the period in the Table is that of the first overtone.
Table. The light elements of double-mode Cepheids
| Star name | Epoch, JD | Period, d | |
| DZ | CMa | 2451873.680 | 2.311200 |
| Y | Car | 2451877.400 | 3.639700 |
| EY | Car | 2451877.470 | 2.876100 |
| GZ | Car | 2451875.800 | 4.160300 |
| UZ | Cen | 2451879.400 | 3.334300 |
| BK | Cen | 2451878.400 | 3.174000 |
| V1048 | Cen | 2451871.660 | 0.922400 |
| VX | Pup | 2451878.360 | 3.011400 |
| BE | Pup | 2427810.457 | 2.871400 |
| EW | Sct | 2451977.900 | 5.816099 |
| V367 | Sct | 2451980.500 | 6.292720 |
| V458 | Sct | 2447733.420 | 4.841250 |
| BQ | Ser | 2452151.000 | 4.270270 |
| U | TrA | 2443267.140 | 2.568423 |
| AP | Vel | 2451878.380 | 3.127200 |
| AX | Vel | 2443878.900 | 3.673145 |
The observations themselves are available in the file attached to the html version of the paper.
The light curves folded with elements from the Table are displayed in Figs. 1-3.
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Fig. 1. The light curves of the double-mode Cepheids DZ CMa, Y Car, EY Car, GZ Car, UZ Cen, BK Cen, V1048 Cen. |
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Fig. 2. The light curves of the double-mode Cepheids VX Pup, BE Pup, EW Sct, V367 Sct, V458 Sct, BQ Ser, U TrA. |
Acknowledgments: This work was supported by the Russian
Foundation for Basic Research (projects No. 18-02-00890 and No.
19-02-00611).
References:
Antipin, S.V., 1997, IBVS, No.4485
Berdnikov, L.N., 1992, Soviet Astronomy Letters, 18, 259
Berdnikov, L.N., Turner, D.G., 2004, Astron. Astrophys. Trans., 23, 253
Cousins, A.W.J., 1976, Mem. RAS, 81, 25
Hacke, G., Richert, M., 1990, Veröff. Sternwarte Sonneberg, 10, 336, 1990
Pojmanski, G., 2002, Acta Astron., 52, 397
Samus, N.N., Kazarovets, E.V., Durlevich, O.V., Kireeva, N.N., Pastukhova, E.N., 2017, Astronomy Reports, 61, 80