Multicolor Photometry of Peculiar
Cepheid Stars Observed in the Konkoly Observatory
B. Cseh1, L. Szabados1, L. Moln´ar1, E. Plachy1, E. Szegedi-Elek1, P. Klagyivik2·3, G. Marschalk´o4, A. Mo´or1, A. Szing4and K. Vida1
1. Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly Thege M. ´ut 15-17, Hungary 2. Instituto de Astrof´ısica de Canarias, C. V´ıa L´actea S/N, 38205 La Laguna, Tenerife,
Spain
3. Universidad de La Laguna, Dept. de Astrof´ısica, 38206 La Laguna, Tenerife, Spain 4. Baja Astronomical Observatory of Szeged University, H-6500 Baja, Szegedi ´ut, Kt.
766, Hungary
We present our preliminary light curves for Cepheid targets with the aim to check the possible period and color index variation of the stars.
The observations were carried out with the 60/90 Schmidt telescope at the Konkoly Observatory Piszk´estet˝o Mountain Station between 2011 and 2015 using Bessel BV RI filters. The reduction of the frames (including bias, dark, and flat corrections and aperture photometry) was performed with the FITSH package (P´al, 2012). Some of the program stars show strong period changes or even cycle to cycle variations that our observations clearly confirm. We display here the O–C diagram for S Vul in Fig. 1 andV band light curves for two Classical Cepheids: CF Cas and S Vul, two Anomalous Cepheids: BW Com and DT Gem, and two Type II Cepheid stars: AU Peg and IX Cas in Fig. 2, respectively.
Acknowledgements. This project has been supported by the Lend¨ulet LP2014-17 Program of the HAS, and by the K-113117, K-115709, K-109276 and PD-121203 grants of the Hun- garian National Research, Development and Innovation Office. LM, EP and KV were supported by the J´anos Bolyai Research Scholarship of the HAS.
References
Mahmoud, F., Szabados, L.,Information Bulletin on Variable Stars 1895(1980) P´al, A.,MNRAS 421, 1825 (2012)
Pojmanski, G., Pilecki, B., Szczygiel, D.,Acta Astron.55, 275 (2005)
pta.edu.pl/proc/v6p287 PTA Proceedings?June, 2018?vol. 6?287
B. Cseh, et al.
-30 -20 -10 0 10 20 30 40 50
-700 -600 -500 -400 -300 -200 -100 0 100 200 -0.4 -0.2 0 0.2 0.4 0.6
O-C [days] Pulsation phase
Epoch
C = 2444147.253+68.0*E
Fig. 1: O–C diagram for S Vul showing the period variation of the star. The blue points are from Mahmoud & Szabados (1980), the black point is from the ASAS Catalogue of Variable Stars (Pojmanski et al., 2005), while the red point is calculated from our new observations.
288?PTA Proceedings?June, 2018?vol. 6 pta.edu.pl/proc/v6p287
Multicolor Photometry of Peculiar Cepheid Stars
10.7 10.8 10.9 11 11.1 11.2 11.3 11.4 11.5
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase CF Cas, P = 4.87554 days
5800 6000 6200 6400 6600 6800 7000 7200 7400
[JD-2450000]
9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase S Vul, P = 69.93452 days
6400 6600 6800 7000 7200 7400
[JD-2450000]
14.35 14.4 14.45 14.5 14.55 14.6 14.65 14.7 14.75 14.8
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase BW Com, P = 0.73361 days
5800 6000 6200 6400 6600 6800 7000 7200 7400
[JD-2450000]
12.2 12.3 12.4 12.5 12.6 12.7 12.8
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase DT Gem, P = 0.61129 days
5800 6000 6200 6400 6600 6800 7000 7200 7400
[JD-2450000]
8.95 9 9.05 9.1 9.15 9.2 9.25 9.3 9.35 9.4
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase AU Peg, P = 2.41254 days
6400 6600 6800 7000 7200 7400
[JD-2450000]
11 11.1 11.2 11.3 11.4 11.5 11.6 11.7
0 0.2 0.4 0.6 0.8 1 1.2 1.4
V mag
pulsation phase IX Cas, P = 9.14897 days
6400 6600 6800 7000 7200 7400
[JD-2450000]
Fig. 2:V band light curves for Classical Cepheids: CF Cas and S Vul, Anomalous Cepheids:
BW Com and DT Gem, and Type II Cepheid stars: AU Peg and IX Cas.
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