1No.103

Oct. 2022

ISSN 0917-2211

Variable Star Bulletin
The TESS light curves of three short period Algol-type systems; X Tri is a real pulsator.
Shin-ya Narusawa
Center for Astronomy, University of Hyogo, Sayo-cho, Hyogo, 679-5313, Japannarusawa@nhao.jp
andKazoo Nagai
Variable Star Observers League in Japan
Received 2022 Oct. 16
δ Sct type oscillations have been discovered in component of many binary systems. Currently, more than 230
eclipsing binary systems with a δ Sct component are known (Liakos et al. 2022). Primary stars of short-periodAlgol-type systems TV Cas (B9 V), R CMa (F1 V) and X Tri (A3 V) are also candidates. Reports in this relationof R CMa and X Tri are summarized in Table 1 and 2, respectively. A pulsation has been suspected in TV Cas
by Tiwari et al. (2011), however a detailed analysis is yet to be published.
We searched for the high-precision photometry of three systems taken in a 2 minute of the TESS mission(Ricker et al. 2015). The ﬂux measurements labeled SAP Flux from the Mikulski Archive for Space Telescopes(MAST) 1 were obtained. The log of observations for each system is given in Table 3.
As a result, quasi-periodic (20 - 40 min.) variations were veriﬁed in X Tri, and a typical sample is shown inFigure 1. To search for the dominant frequency, the PERIOD04 software of Lenz & Breger (2005) was used forthe out of eclipse part (9127 points) of the light curves, and the signal of 38.08 cd−1 (period of about 38 min.)was obtained. Considering the spectral type (A3 V) and the pulsational period, the primary component of X Triis regarded as the δ Sct variable. On the other hand, deﬁnitive oscillations were not found in TESS light curveof TV Cas and R CMa.
S. N. wishes to thank Dr. H. Maehara and Dr. H. Naito for their valuable comments. This paper includes
data collected by the TESS mission, which were obtained from MAST. Funding for the TESS mission is provided
by the NASA Explorer Program. The authors wish to thank the TESS team for its support of this work.
Reference:Kim, S. -L., Lee, J. W., Kwon, S. -G., Youn, J. -H, Mkrtichian, D. E. & Kim, C. 2003 A&A 405, 231
Lehmann, H., Tsymbal, V., Pertermann, F., Tkachenko, A., Mkrtichian, D. E. & A-thano, N. 2018 A&A 615,A131
Lenz, P. & Breger, M. 2005 CoAst. 146, 53
Ricker, G. R. et al. 2015 J. Astron. Telesc. Instrum. Syst. 1, 014003
Liakos, A. & Niarchos, P. 2009 CoAst. 160, 2
Liakos, A. et al. 2022 A&A 663, A137
Mkrtichian, D. E. & Gamarova, A. Yu. 2000 IBVS No. 4836
Mkrtichian, D. E. et al. 2006 ApSS 304, 169
Shimoji, Y. 2015 private communications
Shirakami, K. 2018 Proceedings of the Meeting of Binary Systems, Variable Stars and Late-Type Stars, held 7-9December, 2018. (in Japanese)@1 https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html

2Tiwari, S. K., Pandey, U. S., Chaubey, U., S., Tripathi, A., Deb, S. & Pandey, C. P. 2011 Proceedings of the
29th Meeting of the Astronomical Society of India, held 23-25 February, 2011. ASI Conference Series, Vol. 3,
Edited by P. Khare and C.H. Ishwara-Chandra, 2011, p. 122
Turner, G., Kaitchuck, R. & Holaday, J. 2014 JAAVO 42, 13465600

Flux65200

64800

64400

64000

63600
1766.281766.31

1766.34

1766.37

1766.40

1766.43

1766.46

HJD 2457000+

Figure 1: A typical sample of TESS LCs of X Tri (around Max I).

Table 1: Reports concerning the pulsation of R CMa.
Obs. Datepulsation?

Reference

1955-1956
2001.01.27
2016 Jan., 2017 Jan.

Yes (Ppul = 68 min.)No
Yes (Ppul = 67 min.)Mkrtichian & Gamarova (2000)
Mkrtichian et al. (2006)
Lehmann et al. (2018)

3

Table 2: Reports concerning the pulsation of X Tri
Obs. Datepulsation?

Reference

2001 Dec.
2006 -2008
2007 Jun. - 2008 Dec.
2010 Oct.
2012 - 13
Jul. - Nov. 2018weak signals around 48 and 32 min.
YesNo
Yes (Ppul = 32 min.)Yes: (Ppul = 29 min.)Yes (Ppul = 36 min.)Kim et al. (2003)
Tiwari et al. (2011)
Liakos & Niarchos (2009)
Turner et al. (2004)
Shimoji (2015)
Shirakami (2018)

Table 3: TESS log of observations.
StarTV Cas

TIC No.
327583823

R CMa

409319605

X Tri

28391714

Obs. Date
2019.10.08 - 11.02
2019.11.03 - 11.27
2020.04.16 - 05.12
2019.01.08 - 02.01
2020.12.18 - 2021.01.13
2021.01.14 - 02.08
2019.10.08 - 11.02

Sector
171824733
34
17Camera
2
3
4
2
2
2
1

VSOLJ
c/o Keiichi Saijo National Science Museum, Ueno-Park, Tokyo Japan
Editor Seeichiro Kiyota
e-mail:skiyotax@gmail.com