KIC 6220497: A New Algol-type Eclipsing Binary with Multiperiodic Pulsations
| Autor: | J.-R. Koo, Seung-Lee Kim, Kyeongsoo Hong, Jae Woo Lee |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
010308 nuclear & particles physics Star (game theory) FOS: Physical sciences Astronomy and Astrophysics Astrophysics Type (model theory) Surface gravity Light curve Orbital period 01 natural sciences Stars Amplitude Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences Roche lobe 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) |
| Popis: | We present both binarity and pulsation of KIC 6220497 from the {\it Kepler} observations. The light curve synthesis shows that the eclipsing system is a semi-detached Algol with parameters of $q$ = 0.243$\pm$0.001, $i$ = 77.3$\pm$0.3 deg, and $\Delta T$ = 3,372$\pm$58 K, in which the detached primary component fills its Roche lobe by $\sim$87\%. A multiple frequency analysis of the eclipse-subtracted light residuals reveals 33 frequencies in the range of 0.75$-$20.22 d$^{-1}$ with amplitudes between 0.27 and 4.56 mmag. Among these, four are pulsation frequencies in fundamental ($f_1$, $f_5$) and $p$ ($f_2$, $f_7$) modes, and six are orbital frequency ($f_8$, $f_{31}$) and its harmonics ($f_6$, $f_{11}$, $f_{20}$, $f_{24}$), which can be attributed to tidally excited modes. For the pulsation frequencies, the pulsation constants of 0.16$-$0.33 d and the period ratios of $P_{\rm pul}/P_{\rm orb}$ = 0.042$-$0.089 indicate that the primary component is a $\delta$ Sct pulsating star and, thus, KIC 6220497 is an oscillating eclipsing Algol (oEA) star. The dominant pulsation period of 0.1174051$\pm$0.0000004 d is significantly longer than that expected from empirical relations that link the pulsation period with the orbital period. The surface gravity of $\log g_1$ = 3.78$\pm$0.03 is clearly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved EB, compared with normal oEA stars. Comment: 15 pages, including 8 figures and 2 tables, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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