Exploring the helium core of the delta Scuti star CoRoT 102749568 with asteroseismology

Abstract

Based on regularities in rotational splittings, we seek possible multiplets for the observed frequencies of CoRoT 102749568. Twenty-one sets of multiplets are identified, including four sets of multiplets with $l=1$, nine sets of multiplets with $l=2$, and eight sets of multiplets with $l=3$. In particular, there are three complete triplets ($f_{10}$, $f_{12}$, $f_{14}$), ($f_{31}$, $f_{34}$, $f_{35}$), and ($f_{41}$, $f_{43}$, $f_{44}$). The rotational period of CoRoT 102749568 is estimated to be $1.34_{-0.05}^{+0.04}$ days. When doing model fittings, three $l=1$ modes ($f_{12}$, $f_{34}$, and $f_{43}$) and the radial first overtone $f_{13}$ are used. Our results shows that the three nonradial modes ($f_{12}$, $f_{34}$, and $f_{43}$) are mixed modes, which mainly provide constraints on the helium core. The radial first overtone $f_{13}$ mainly provides constraint on the stellar envelope. Hence the size of the helium core of CoRoT 102749568 is determined to be $M_{\mathrm{He}}$ = 0.148 $\pm$ 0.003 $M_{\odot }$ and $R_{\mathrm{He}}$ = 0.0581 $\pm$ 0.0007 $R_{\odot }$. The fundamental parameters of CoRoT 102749568 are determined to be $M$ = 1.54 $\pm$ 0.03 $M_{\odot }$, $Z=$ 0.006, $f_{\mathrm{ov}}$ = 0.004 $\pm$ 0.002, $\log g$ = 3.696 $\pm$ 0.003, $T_{\mathrm{eff}}$ = 6886 $\pm$ 70 K, $R$ = 2.916 $\pm$ 0.039 $R_{\odot }$, and $L$ = 17.12 $\pm$ 1.13 $L_{\odot }$.

arXiv commentThe paper is accepted for publication in The Astrophysical Journal. 5 figures and 8 Tables

References in corpus (21)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• The Dartmouth Stellar Evolution Database
• The evolution of rotating stars
• ADIPLS -- the Aarhus adiabatic oscillation package
• Acoustic oscillations in rapidly rotating polytropic stars I. Effects of the centrifugal distortion
• Asteroseismic analysis of the CoRoT δ-Scuti star HD174936
• Evidence for a sharp structure variation inside a red-giant star
• Can rotation explain the multiple main sequence turn-offs of Magellanic Cloud star clusters?
• Regularities in frequency spacings of Delta Scuti stars: The Kepler star KIC 9700322
• An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy. Large separation as a new observable for δSct stars
• Effects of rotation on the evolution and asteroseismic properties of red giants
• Pulsation spectrum of Delta Sct stars: the binary HD 50870 as seen with CoRoT and HARPS
• Unexpected series of regular frequency spacing of delta Scuti stars in the non-asymptotic regime -- I. The methodology
• Convective overshoot mixing in stellar interior models
• WIYN Open Cluster Study LXII: Comparison of Isochrone Systems using Deep Multi-Band Photometry of M35
• Regular frequency patterns in the classical delta Scuti star HD 144277 observed by the MOST satellite
• CoRoT 102749568: mode identification in a delta Scuti star based on regular spacings
• Asteroseismic analysis of solar-mass subgiants KIC 6442183 and KIC 11137075 observed by Kepler
• Asteroseismology of the $\delta$ Scuti star HD 50844
• Grids of rotating stellar models with masses between 1.0 and 3.0 Msun

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