Asteroseismology of the $\delta$ Scuti star HD 50844

Abstract

Aims. We aim to probe the internal structure and investigate more detailed information of the $\delta$ Scuti star HD 50844 with asteroseismology. Methods. We analyse the observed frequencies of the $\delta$ Scuti star HD 50844 obtained by Balona (2014), and search for possible multiplets based on the rotational splitting law of g-mode. We tried to disentangle the frequency spectra of HD 50844 by means of the rotational splitting only. We then compare them with theoretical pulsation modes, which correspond to stellar evolutionary models with various sets of initial metallicity and stellar mass, to find the best-fitting model. Results. There are three multiplets including two complete triplets and one incomplete quintuplet, in which mode identifications for spherical harmonic degree $l$ and azimuthal number $m$ are unique. The corresponding rotational period of HD 50844 is found to be 2.44${}_{-0.08}^{+0.13}$ days. The physical parameters of HD 50844 are well limited in a small region by three modes identified as nonradial ones ($f_{11}$, $f_{22}$, and $f_{29}$) and by the fundamental radial mode ($f_4$). Our results show that the three nonradial modes ($f_{11}$, $f_{22}$, and $f_{29}$) are all mixed modes, which mainly represent the property of the helium core. The fundamental radial mode ($f_4$) mainly represents the property of the stellar envelope. In order to fit these four pulsation modes, both the helium core and the stellar envelope must be matched to the actual structure of HD 50844. Finally, the mass of the helium core of HD 50844 is estimated to be 0.173 $\pm$ 0.004 $M_{\odot }$ for the first time. The physical parameters of HD 50844 are determined to be $M=$ 1.81 $\pm$ 0.01 $M_{\odot }$, $Z=$ 0.008 $\pm$ 0.001. $T_{\mathrm{eff}}=$ 7508 $\pm$ 125 K, log$g=$ 3.658 $\pm$ 0.004, $R=$ 3.300 $\pm$ 0.023 $R_{\odot }$, $L=$ 30.98 $\pm$ 2.39 $L_{\odot }$.

arXiv comment11 pages, 7 figures, 6 tables, accepted for publication in A&A

References in corpus (18)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Low Temperature Opacities
• ADIPLS -- the Aarhus adiabatic oscillation package
• Acoustic oscillations in rapidly rotating polytropic stars I. Effects of the centrifugal distortion
• Imaging and Modeling Rapidly Rotating Stars: Alpha Cephei and Alpha Ophiuchi
• Detection of 75+ pulsation frequencies in the Delta Scuti star FG Vir
• A new method for the spectroscopic identification of stellar non-radial pulsation modes. II. Mode identification of the Delta Scuti star FG Virginis
• An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy. Large separation as a new observable for δSct stars
• Inferences from pulsational amplitudes and phases for multimode $\delta$ Sct star FG Vir
• Pulsation spectrum of Delta Sct stars: the binary HD 50870 as seen with CoRoT and HARPS
• Mode density and frequency extraction in the delta Scuti star HD 50844
• A delta Scuti star in the post-MS contraction phase: 44 Tauri
• Preparing the COROT space mission: new variable stars in the galactic Anticenter direction
• An asteroseismic study of the Delta Scuti star 44 Tau
• Discovery of binarity, spectroscopic frequency analysis, and mode identification of the delta Sct star 4CVn
• Matching the Spectral Energy Distribution and p Mode Oscillation Frequencies of the Rapidly Rotating Delta Scuti Star ? Ophiuchi with a 2D Rotating Stellar Model
• Simultaneous intensive photometry and high resolution spectroscopy of Delta Scuti stars. V. The high--degree modes in the pulsational content of BV Circini

Cited by in corpus (12)

• KIC 10736223: An Algol-type eclipsing binary just undergone the rapid mass-transfer stage
• Unveiling $\delta$ Scuti and $\gamma$ Doradus Hybrid Pulsation of HD 53166 and HD 53349 Plus Rich Frequencies in HD 52788 -- Catalogs of 70552 $\delta$ Sct and 8080 $\gamma$ Dor
• Exploring the helium core of the delta Scuti star CoRoT 102749568 with asteroseismology
• Rotational splitting and asteroseismic modelling of the delta Scuti star EE Camelopardalis
• Seismology of Altair with MOST
• The Delta Scuti star 38 Eri from the ground and from space
• Determining the evolutionary stage of the delta Scuti star HIP 80088 with asteroseismology
• Exploring the convective core of the high-amplitude $\delta$ Scuti star TIC 120857354 with asteroseismology
• Asteroseismology of the pre-main-sequence $\delta$ Scuti pulsator IP Persei
• KIC 12268220: A $\delta$ Scuti Pulsating Star and an Active Protohelium White Dwarf in an Eclipsing Binary System
• EPIC 202843107 : A Close Eclipsing Binary Containing a δ Scuti Variable
• OO Dra: an Algol-type binary formed through an extremely helium-poor mass accretion revealed by asteroseismology