Absolute Properties of the Oscillating Eclipsing Algol X Trianguli

Abstract

We report results from the TESS photometric data and new high-resolution spectra of the Algol system X Tri showing short-period pulsations. From the echelle spectra, the radial velocities of the eclipsing pair were measured, and the rotational rate and effective temperature of the primary star were obtained to be $v_1$$\sin$$i=84\pm 6$ km s${}^{-1}$ and $T_{\mathrm{eff},1}=7900\pm 110$ K, respectively. The synthetic modeling of these observations implies that X Tri is in synchronous rotation and is physically linked to a visual companion TIC 28391715 at a separation of about 6.5 arcsec. The absolute parameters of our target star were accurately and directly determined to be $M_1=2.137\pm 0.018$ $M_{\odot }$, $M_2=1.101\pm 0.010$ $M_{\odot }$, $R_1=1.664\pm 0.010$ $R_{\odot }$, $R_2=1.972\pm 0.010$ $R_{\odot }$, $L_1=9.67\pm 0.55$ $L_{\odot }$, and $L_2=2.16\pm 0.09$ $L_{\odot }$. The phase-binned mean light curve was used to remove the binary effect from the observed TESS data. Multifrequency analysis of the residuals revealed 16 significant frequencies, of which the high-frequency signals between 37 day${}^{-1}$ and 48 day${}^{-1}$ can be considered probable pulsation modes. Their oscillation periods of 0.021$-$0.027 days and pulsation constants of 0.014$-$0.018 days are typical values of $\delta$ Sct variables. The overall results demonstrate that X Tri is an oEA star system, consisting of a $\delta$ Sct primary and its lobe-filling companion in the semi-detached configuration.

27 pages, including 8 figures and 6 tables, accepted for publication in AJ

References in corpus (14)

• The Transiting Exoplanet Survey Satellite
• A heuristic derivation of the uncertainty of the frequency determination in time series data
• The BOES spectropolarimeter for Zeeman measurements of stellar magnetic fields
• Eclipsing binary stars with a $\delta$ Scuti component
• Discovery of $\beta$ Cep pulsations in the eclipsing binary V453 Cygni
• The Eclipsing System V404 Lyr: Light-Travel Times and Gamma Doradus Pulsations
• Absolute Properties of the Pulsating Post-mass Transfer Eclipsing Binary OO Draconis
• Asteroseismology of Kepler Algol type oscillating eclipsing binaries
• The Pre-He White Dwarfs in Eclipsing Binaries. I. WASP 0131+28
• Absolute Properties of the Eclipsing $\gamma$ Dor Star V404 Lyrae
• The Pulsating Eclipsing Binary TIC 309658221 in a 7.59 Day Orbit
• The Pre-He White Dwarfs in Eclipsing Binaries. IV. WASP 1814+48 with Multiperiodic Pulsations
• Tidally Excited Modes and $\delta$ Scuti Pulsations in the Eclipsing Triple Star IM Persei
• The Pre-He White Dwarfs in Eclipsing Binaries. III. WASP 1625-04