CC BY
10Peremennye Zvezdy ( Variable ¡Stars) 42, No. 5, 2022
Received 2 June; accepted 14 June.
DOI: 10.24412/2221-0474-2022-42-28-34
A Study of Double-mode High-amplitude 6 Scuti Variable Stars Pulsating in the Fundamental and First Overtone Modes. II
A. V. Khruslov1'2
1 Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetskij pr. 13, Moscow 119992, Russia; khruslov@bk.ru
2 Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya str. 48, Moscow 119017, Russia
I present a detection of 44 new double-mode high-amplitude S Scuti variable stars, HADS(B) type, pulsating in the fundamental and first overtone modes. We analyzed all observations available for these stars in the ASAS-SN online public archive using the period-search software developed by Dr. V.P. Goranskij for Windows environment. Additionally, in individual cases, I used data of the SuperWASP, CSS, and ASAS-3 surveys. Light elements and parameters of the light curves of both oscillations were obtained.
1 Introduction
In the course of my study of high-amplitude 8 Scuti variable stars (HADS) included in the ASAS-SN Variable Stars Database (Jayasinghe et al., 2018, 2019a, 2019b, 2020, 2021), I discovered 44 new double-mode HADS variables, pulsating in the fundamental and first overtone modes. This article continues my previous paper (Khruslov, 2021). Searching for double periodicity, I mainly used data available in the photometric archive of the All-Sky Automated Survey for Supernovae (ASAS-SN, Shappe et al., 2014, Kochanek et al., 2017). Additionally, I analyzed available data from other archives: the Wide Angle Search for Planets (SuperWASP, Butters et al., 2010), the Catalina Sky Surveys (Drake et al., 2009), the All Sky Automated Survey (ASAS-3, Pojmanski, 2002).
The SuperWASP observations are available as FITS tables, which were converted into ASCII tables using the OMC2ASCII1 program as described by Sokolovsky (2007).
The method used to search for multiperiodicity is similar to that described in my previous paper (Khruslov, 2021).
The light curves and data from the ASAS-SN survey are available online in the html version of this paper as a zip-archive. The light curves are given in the format displayed in Fig. 1.
The radial pulsation modes were identified by the period ratio (Pshort/Plong). The period ratio of pulsations in the fundamental and first-overtone modes typical of doublemode HADS stars (F/1O) is P1/P0 = 0.75 — 0.78 (Petersen & Christensen-Dalsgaard, 1996).
The stars were identified in the GSC 1.2 (Morrison et al., 2001) and USN0-B1.0 (Monet et al., 2003) catalogs. The tabulated coordinates of the variables were drawn from the Gaia DR2 catalog (Gaia Collaboration, Brown et al., 2018).
1 http://scan.sai.msu.ru/swasp_converter/
Table 1. Positions, identifications, and magnitudes
No. Coordinates (J2000) GSC USN0-B1.0 V, mag Comments
1 12 08 10.53 -49 54 25.5 - 0400-0287767 14.02- 14.57 1
2 12 10 23.35 -45 31 09.9 - 0444-0276786 14.90- 15.46 2
3 12 16 31.56 -36 04 09.0 - 0539-0264614 15.12- 15.72 2
4 12 17 43.89 -11 46 42.2 05529-01386 0782-0272273 13.98- 14.33 2,3,4
5 12 32 21.34 -24 02 27.6 06682-00414 0659-0275812 14.30- 14.73 1,2,5
6 12 45 59.08 -24 37 35.7 06688-00945 0653-0279223 14.40- 15.15 2,6
7 12 49 45.36 +04 01 38.0 - 0940-0209227 14.4- 15.0 2,7,8
8 12 59 13.60 -44 46 02.0 07784-01897 0452-0297280 14.30- 14.94 1,9
9 13 16 19.13 -37 52 14.3 07774-00834 0521-0364332 12.75- 13.14 1,2
10 13 24 50.14 -33 00 58.0 07268-00499 0569-0376858 14.52- 15.11 1,2
11 13 29 01.45 -50 14 48.1 - 0397-0345242 15.2- 15.7 1
12 13 29 25.93 -42 59 51.2 07795-02020 0470-0348501 12.66- 13.31 5,10
13 13 33 53.05 +55 30 41.1 03853-00366 1455-0228972 13.30- 13.59 1,7
14 13 35 40.37 -45 31 12.0 08261-01377 0444-0321790 12.20- 12.63 1,2,5
15 13 48 09.81 -46 55 53.3 08266-03128 0430-0377207 14.47- 15.35 1
16 13 50 07.59 -37 01 30.0 07291-01796 0529-0369256 13.41- 13.88 1,5
17 13 55 03.49 -09 58 37.4 05553-00969 0800-0254490 14.5- 14.9 -
18 13 59 10.53 -43 24 52.8 07802-00349 0465-0307388 14.55- 15.28 1
19 14 12 06.96 -26 10 06.8 06734-00964 0638-0321431 13.60- 14.10 1
20 14 52 11.10 -46 09 36.3 08280-00902 0438-0387168 13.15- 13.45 2,5
21 14 53 13.45 -39 49 29.8 07824-01293 0501-0333265 13.76- 14.16 1
22 14 53 53.44 -34 43 53.2 07306-02118 0552-0337321 13.97- 14.61 1,2,5
23 15 11 30.55 -44 00 13.5 07834-02176 0459-0376147 13.43- 14.02 1,2,5
24 15 20 00.03 -14 06 27.0 05606-01060 0758-0304698 14.05- 14.52 -
25 15 25 39.01 -68 19 11.1 - 0216-0487098 14.4 -14.8 1
26 15 27 33.88 -67 58 49.1 09259-01071 0220-0632544 11.97- 12.48 11,12
27 15 28 01.67 -39 18 40.7 07835-01463 0506-0367781 12.54- 13.01 1,5
2 Results
In the 12h — 22h right ascension interval, I detected 44 new HADS(B) stars pulsating in the fundamental and first-overtone modes. Their magnitudes are between 10m8 and 15m7 in the V band of the ASAS-SN photometric system. The highest peak-to-peak amplitude of light variations is 0m88. The fundamental-mode periods are between 0d049 and 0d 198.
The light curves for one of the stars (No. 40) are displayed in Fig. 1. The top panels present data folded with the fundamental-mode and first overtone periods. The bottom panels show the same curves after prewhitening the other oscillation (if /i+/o, fi — fo and /i+2/o interaction frequencies or non-radial frequencies were excluded, it is also noted). Along with the light curves, we present power spectra of the double-mode variables, for the raw data and after subtraction of the dominant mode (fundamental or first-overtone oscillations). The structure of the power spectra shows that the secondary periods are real.
Information on these stars is presented in Tables 1 and 2. Table 1 contains equatorial coordinates (J2000); star numbers from the GSC and USN0-B1.0 catalogs; magnitudes at maximum and minimum in the V band of the ASAS-SN photometric system; number for comments on individual stars, which are given below the table.
Table 1 (continued).
No. Coordinates (J2000) GSC USN0-B1.0 V, mag Comments
28 15 38 37.24 -27 16 08.6 06785-00473 0627-0454963 12.27- 12.81 1,4,5,13,14
29 15 39 41.12 -41 46 03.7 - 0482-0418461 14.70- 15.26 1
30 15 56 13.31 -79 00 28.9 09437-01620 0109-0087589 14.49- 15.14 1,15
31 16 10 08.32 -67 55 22.2 09273-02948 0220-0666009 12.80- 13.00 1,13,16
32 16 10 45.10 + 14 32 37.4 - 1045-0266321 15.10- 15.70 2,4,7
33 16 22 17.73 -66 39 43.7 09049-02231 0233-0607471 12.98- 13.27 1,17
34 16 50 24.32 -51 54 31.1 08338-02654 0380-0739083 10.86- 11.18 1,13
35 16 50 46.20 -84 24 26.6 09526-00038 0055-0045940 14.13- 14.62 1
36 17 06 50.85 -60 11 22.5 - 0298-0712396 13.80- 14.27 1
37 17 20 30.67 -53 00 23.6 - 0369-0906568 13.96- 14.33 1
38 17 57 08.63 +08 46 59.3 - 0987-0333844 13.67- 13.97 7
39 18 07 56.92 +09 01 48.9 01009-00503 0990-0334368 11.42- 11.65 13,18
40 18 10 10.48 +78 28 41.5 04574-01244 1684-0067406 13.73- 14.60 1
41 18 11 00.53 +23 33 52.5 - 1135-0277930 14.47- 15.17 1
42 18 53 03.53 +34 19 56.7 02646-00538 1243-0294533 13.91- 14.29 2,7
43 21 33 05.07 +20 42 19.4 01676-00916 1107-0562696 12.22- 12.49 13
44 21 52 30.71 +21 02 09.0 01691-01258 1110-0569052 12.30- 12.58 -
Comments to Table 1.
1. The variability was detected in the ASAS-SN survey, type HADS.
2. The star is contained in the Gaia DR2 catalog as a variable, type DSCT or SXPHE.
3. The variable is contained in the Catalina surveys periodic variable star catalog (Drake et al., 2014), the type HADS and a wrong period, P = 0d0879278, are given. In the ASAS-SN Variable Stars Database, the type RRC and the period P = 0d3232124 = 4Po are given.
4. Data from the Catalina survey (CSS or SSS) were used to improve the light elements.
5. Data from 1SWASP were used to improve the light elements.
6. The variability was discovered by Denis Denisenko (announcement of May 17, 2017 in the AAVSO Variable Star Index, DDE110).
7. The variable is contained in the ZTF catalog (Chen et al., 2020), type DSCT.
8. The variability was detected by Palaversa et al. (2013), LINEAR 7834923, type 8 Sct or SX Phe is given.
9. Additional non-radial pulsation, Pn = 0d06059591, An = 0.017.
10. The variability was announced in GALEX TDS Alerts (May 2008 archive2). Later, Patrick Wils (announcement of October 05, 2010 in the AAVSO Variable Star Index) classified this variable as a HADS star.
11. The variability was detected in the ASAS-SN survey, type RRc.
12. Additional non-radial pulsation, Pn = 0d 11779922, An = 0.018.
13. Data from the ASAS-3 survey were used to improve the light elements.
14. Better identification compared to GSC and USN0-B1.0: 2MASS15383724-2716085.
15. A close faint companion can somewhat influence the ASAS-SN photometry, amplitude is underestimated.
16. Light elements improved only for f0.
17. P0 possibly varies.
2 http://www.galex.caltech.edu/researcher/alerts_archive/0805/
18. The variability was detected in the ASAS-3 survey (Pojmanski, 2002), type DSCT.
Figure 1. The light curves and power spectra of the star No. 40 (GSC 04574-01244) from ASAS-SN data.
Table 2 presents the light elements (period in days and epoch of maximum, E = HJD — 2457777.0), semi-amplitude and asymmetry parameter M — m for the fundamental mode (P0, E0, A0, and M—m) and first-overtone mode (P1, E1, A1 and M—m) oscillations, and the period ratio P1/P0.
The information on detected interaction frequencies is contained in Table 3: periods and semi-amplitudes of the frequencies f1+/0, f1 — /0, and f1+2/0.
The Petersen diagram for double-mode HADS variables pulsating in the fundamental and first overtone modes, studied in this paper, is displayed in Fig. 2.
Acknowledgments: The author wishes to thank Dr. V.P. Goranskij for providing his software.
Erratum: In my previous paper (Khruslov, 2021), in Table 2, the epochs of maximum E0 and E1 should be understood in accordance with the rule E = HJD —2457777.0, similar to designations in the present article.
Table 2. Light elements and light-curve parameters
No. Po Eo Ao M - m Pi Ei Ai M - m Pi/Po
1 0.05421705 0.0288 0.130 0.48 : 0.04245730 0.0030 0.028 0.50 0.7831
2 0.0605625 0.0310 0.045 0.48 0.04693815 0.0056 0.135 0.38 0.7750
3 0.0760321 0.0537 0.108 0.44 0.0588474 0.0360 0.081 0.46 0.7740
4 0.08080310 0.0435 0.078 0.38 0.06262673 0.0583 0.038 0.47 0.7751
5 0.05299097 0.0190 0.144 0.43 0.04129606 0.0344 0.014 0.43 0.7793
6 0.07349022 0.0402 0.075 0.43 0.05787771 0.0138 0.142 0.44 0.7876
7 0.04835323 0.0397 0.109 0.45 0.03790137 0.0172 0.033 0.47 0.7838
8 0.1060661 0.0987 0.163 0.39 0.0819442 0.0125 0.040 0.42 0.7726
9 0.05385044 0.0027 0.125 0.43 0.04153844 0.0150 0.032 0.50 0.7714
10 0.0632775 0.0331 0.145 0.42 0.0488963 0.0438 0.058 0.40 0.7727
11 0.0668803 0.0535 0.071 0.44 0.0516401 0.0476 0.065 0.44 0.7721
12 0.07248921 0.0527 0.218 0.37 0.05637456 0.0528 0.034 0.50 0.7777
13 0.0545291 0.0104 0.081 0.46 0.0425803 0.0310 0.017 0.50 0.7809
14 0.11808945 0.0815 0.044 0.49 0.09104399 0.0080 0.135 0.40 0.7710
15 0.1063900 0.0818 0.195 0.38 0.0822725 0.0050 0.063 0.38 0.7733
16 0.09540190 0.0344 0.150 0.37 0.07388515 0.0620 0.028 0.48 0.7745
17 0.0909756 0.0420 0.067 0.44 0.0707977 0.0160 0.038 0.59 0.7782
18 0.0981587 0.0340 0.152 0.40 0.0758572 0.0625 0.097 0.40 0.7728
19 0.05489456 0.0384 0.091 0.41 0.04244899 0.0417 0.078 0.40 0.7733
20 0.05121980 0.0466 0.097 0.48 0.03959064 0.0085 0.016 0.50 0.7730
21 0.0716087 0.0245 0.123 0.38 0.0556071 0.0306 0.018 0.46 0.7765
22 0.07171796 0.0460 0.211 0.32 0.05568080 0.0213 0.036 0.38 0.7764
23 0.11554994 0.0100 0.141 0.40 0.08918751 0.0710 0.047 0.47 0.7719
24 0.05890204 0.0106 0.131 0.40 0.04559278 0.0250 0.023 0.48 0.7740
25 0.1273789 0.0066 0.052 0.47 0.0980794 0.0210 0.043 0.46 0.7700
26 0.1981664 0.1961 0.126 0.30 0.1512945 0.0620 0.040 0.39 0.7635
27 0.08477987 0.0308 0.154 0.37 0.06579935 0.0320 0.025 0.47 0.7761
28 0.0921824 0.0690 0.177 0.36 0.07106444 0.0670 0.030 0.47 0.7709
29 0.1079323 0.0390 0.129 0.35 0.0832761 0.0242 0.038 0.47 0.7716
30 0.06249759 0.0496 0.111 0.40 0.04840073 0.0177 0.063 0.41 0.7744
31 0.11027940 0.0310 0.065 0.45 0.0849659 0.0018 0.017 0.47 0.7705
32 0.0550930 0.0484 0.131 0.46 0.0431698 0.0187 0.028 0.51 : 0.7836
33 0.1520337 0.1486 0.086 0.44 0.1147119 0.0173 0.023 0.45 0.7545
34 0.06819099 0.0044 0.061 0.47 0.05271310 0.0203 0.027 0.47 0.7730
35 0.07040738 0.0415 0.085 0.40 0.05455083 0.0345 0.055 0.45 0.7748
36 0.1053168 0.0053 0.094 0.37 0.0814678 0.0460 0.030 0.44 0.7735
37 0.08752745 0.0864 0.102 0.40 0.0682577 0.0315 0.018 0.50 : 0.7798
38 0.0863452 0.0170 0.063 0.44 0.0671900 0.0033 0.037 0.43 0.7782
39 0.10531333 0.0177 0.075 0.45 0.08136916 0.0816 0.018 0.47 0.7726
40 0.06562886 0.0250 0.247 0.34 0.05083454 0.0467 0.058 0.44 0.7746
41 0.05119872 0.0297 0.211 0.39 0.03992636 0.0087 0.023 0.52 0.7798
42 0.0876665 0.0820 0.096 0.41 0.0676739 0.0545 0.040 0.45 0.7719
43 0.07696904 0.0560 0.061 0.45 0.05958269 0.0319 0.044 0.46 0.7741
44 0.0768717 0.0202 0.061 0.44 0.0596820 0.0021 0.046 0.46 0.7764
Table 3. Information on interaction frequencies
No.
P1+0 A1+0 P1-0 A1-0 P1+20 A1+20
0.02381086 0.020 - - - -
0.02320905 0.009 - - - -
0.03237805 0.033 - - - -
0.04622891 0.022 0.3603088 0.020 - -
0.02344990 0.009 0.18168206 0.009 - -
0.02758248 0.023 - - - -
0.02914020 0.023 - - - -
0.03171217 0.020 0.25358226 0.017 - -
0.05140885 0.016 0.3975195 0.017 - -
0.04639495 0.035 0.3629301 0.031 0.03230665 0.026
0.04163814 0.020 0.3276010 0.014 0.02898677 0.010
0.04278941 0.028 0.3338889 0.038 - -
0.02393807 0.021 0.1872339 0.026 0.01666912 0.011
- - 0.1743745 0.006 - -
- - 0.2488406 0.014 - -
0.03134499 0.021 0.2490127 0.019 - -
0.05033576 0.022 0.3909190 0.021 - -
0.08579321 0.030 - - 0.05987247 0.012
0.03704679 0.014 - - - -
0.04012877 0.018 0.31020314 0.017 0.02795813 0.010
0.02727661 0.023 0.2145814 0.036 - -
0.03073655 0.014 0.2422169 0.018 - -
0.03835072 0.014 - - - -
0.03778613 0.013 - - - -
0.04590280 0.005 0.3578865 0.006 - -
0.02864606 0.037 0.2255053 0.031 0.01994176 0.020
0.02243270 0.015 - - - -
0.0381919 0.013 0.296743 0.010 - -
0.03358449 0.006 0.2637729 0.006 - -
0.03359746 0.010 0.2668983 0.011 - -
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Figure 2. The Petersen diagram for the HADS(B) stars announced in this paper.
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