The Blazhko modulation of TV Boo in 2010

TL;DR

This paper analyzes multicolor CCD observations of the RRc star TV Boo in 2010, revealing complex Blazhko modulation with two independent periods, and identifies an additional non-radial mode frequency.

Contribution

It provides the first detailed analysis of the Blazhko effect in TV Boo, showing dual modulation periods and identifying a likely non-radial pulsation mode.

Findings

Two independent Blazhko modulation periods identified (9.74 d and 21.43 d).

Asymmetry parameters differ from typical RRab stars, indicating unique modulation characteristics.

Detection of an additional frequency likely representing a non-radial pulsation mode.

Abstract

We present the analysis of the multicolour CCD observations in the 2010 season of the Blazhko RRc star TV Boo. TV Boo shows a complex Blazhko modulation dominated by two independent modulations with P_{fm1}=9.74 d and P_{fm2}=21.43 d long periods. Both modulation components appear in the frequency spectra as multiplet structures around the harmonics of the pulsation. The positive value of the asymmetry parameter (Q=+0.51) of the primary modulation suggests that it is similar in its character to the Blazhko effect of most of the modulated RRab stars. Interestingly, the secondary, lower-amplitude modulation exhibits a negative asymmetry parameter (Q=-0.22), which is an unusually low value when compared to the Blazhko-modulated RRab stars. Apart from the two modulation frequencies, the spectra also show an additional frequency f' and its linear combinations with the pulsation and the primary modulation f_{1}+f' and f_{1}-f'-f_{m1}. We conclude that the additional frequency most probably belongs to a non-radial mode.