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Ai-Ying Zhou

Publications and source records attributed to Ai-Ying Zhou.

7 recordsLinked to original sources

Orbital and Pulsation Analysis of 42 Heartbeat Stars Discovered in TESS Data

Heartbeat stars (HBSs) are ideal laboratories for studying the formation and evolution of binary stars in eccentric orbits and their mutual tidal interactions. We present 42 new HBSs discovered based on TESS-SPOC and QLP data. Their physical parameters have been obtained through modeling with appropriate models. Subsequently, Tidally excited oscillations (TEOs) are detected in ten systems, and their pulsation phases and modes are identified. Most pulsation phases can be explained by the dominant being spherical harmonic degree $l=2$ and azimuthal order $m=0$ or $\pm2$. For TIC 156846634, the harmonic with large deviation ($>3σ$) from the expected adiabatic phase can be expected to be a traveling wave or significantly nonadiabatic. The harmonic numbers $n$ = 16 in TIC 184413651 may not be considered as a TEO candidate due to its large deviation ($>2σ$) from the adiabatic expectation. Moreover, TIC 92828790 shows no TEOs but exhibits a significant $γ$\,Dor-type pulsation. The eccentricity-period ($e-P$) relation also shows a positive correlation between eccentricity and period, as well as the existence of orbital circularization. The Hertzsprung-Russell diagram shows that TESS HBSs have higher temperatures and greater luminosities than Kepler HBSs, possibly due to selection effects. This significantly enhances the detectability of massive HBSs and those containing TEOs.

astro-ph.SR

Twenty-three New Heartbeat Star Systems Discovered Based on TESS Data

Heartbeat stars (HBSs) are ideal astrophysical laboratories to study the formation and evolution of binary stars in eccentric orbits and the internal structural changes of their components under strong tidal action. We discover 23 new HBSs based on TESS photometric data. The orbital parameters, including orbital period, eccentricity, orbital inclination, argument of periastron, and epoch of periastron passage of these HBSs are derived by using a corrected version of Kumar et al.'s model based on the Markov Chain Monte Carlo (MCMC) method. The preliminary results show that these HBSs have orbital periods in the range from 2.7 to 20 days and eccentricities in the range from 0.08 to 0.70. The eccentricity-period relation of these objects shows a positive correlation between eccentricity and period, and also shows the existence of orbital circularization. The Hertzsprung-Russell diagram shows that the HBSs are not all located in a particular area. The distribution of the derived parameters suggests a selection bias within the TESS survey towards massive HBSs with shorter orbital periods, higher temperatures and luminosities. These objects are a very useful source to study the structure and evolution of eccentricity orbit binaries and to extend the TESS HBS catalog.

astro-ph.SR

Five New Heartbeat Star Systems with Tidally Excited Oscillations Discovered Based on TESS Data

Heartbeat stars (HBSs) with tidally excited oscillations (TEOs) are ideal astrophysical laboratories for studying the internal properties of the systems. In this paper, five new HBSs exhibiting TEOs are discovered using TESS photometric data. The orbital parameters are derived using a corrected version of Kumar et al.'s model based on the Markov Chain Monte Carlo (MCMC) method. The TEOs in these objects are examined, and their pulsation phases and modes are identified. The pulsation phases of the TEOs in TIC 266809405, TIC 266894805, and TIC 412881444 are consistent with the dominant $l=2$, $m=0$, or $\pm2$ spherical harmonic. For TIC 11619404, although the TEO phase is close to the $m=+2$ mode, the $m = 0$ mode cannot be excluded because of the low inclination in this system. The TEO phase in TIC 447927324 shows a large deviation ($>2σ$) from the adiabatic expectations, suggesting that it is expected to be a traveling wave rather than a standing wave. In addition, these TEOs occur at relatively low orbital harmonics, and we cautiously suggest that this may be an observational bias. These objects are valuable sources for studying the structure and evolution of eccentricity orbit binaries and extending the TESS HBS catalog with TEOs.

astro-ph.SR

Validating Gaia DR3 Pulsating Variable Classifications with TESS: Building Reliable $δ$ Scuti and $γ$ Doradus Stars Catalogs (In Progress)

Gaia DR3 revealed 748,058 pulsating variable stars of mixed DSCT|GDOR|SXPHE types. This project undertakes a comprehensive examination to validate and distinguish these stars using TESS data. Aiming for reliable catalogs of bona fide $δ$ Scuti and $γ$ Doradus stars, I have validated 1715 $δ$ Scuti stars, 1403 $γ$ Doradus stars, and identified 260 eclipsing binaries, one RR Lyrae star, and 460+ rotating variables from an initial sample of 16,690 objects. Notably, 15 of the newfound eclipsing binaries harbor pulsating $γ$ Doradus components.

astro-ph.SR

V1162 Orion: Updated Amplitude and Period Variation

In 2010 November 23-25, we found that the amplitude of V1162 Orion, a {delta} Scuti star, recovered to about 0.18 mag in V band. An updated (O-C) diagram is provided for all available maximum data.

astro-ph.SR

A Review of The O--C Method and Period Change

The classical O--C curves are discussed in different cases in which various period changes involved. Among them, the analytic O--C curves with frequency, amplitude modulations and with double modes are closely inspected, respectively. As a special, the light-time effect is illustrated. The features of period change noise and period change to metallicity are added at the end.

astro-ph

Nonradial pulsation of the $δ$ Scuti star UV Trianguli

We present the results of a three-year photometric study of the $δ$ Scuti star UV Trianguli. Our data sets consist of 9378 differential measurements in Johnson V together with a few data collected into the Strömgren {\em uvby$β$} system. UV Tri is at least a biperiodic variable. The two best-fitting frequencies, $f_1$=9.3298 d$^{-1}$ and $f_2$=10.8513 d$^{-1}$, are still not the complete set of pulsation frequencies representing the star's light variations. A suspected third frequency might present in the star. Several ``anomalous cycles'' are observed in the light curves. They seem real, but are aperiodic. We derive the colour indices and physical parameters for the variable and conclude that it is a Population I $δ$ Sct star with normal metal abundance ([Me/H]=0.0$\pm$n0.1 dex) evolving on its main sequence stage at an early evolutionary phase before the turn-off point. Finally, we compare the observed oscillation frequencies with theoretical models. The two pulsation modes of UV Tri are likely nonradial to be gravity modes.

astro-ph