Constraining the near-core rotation of the gamma Doradus star 43 Cygni using BRITE-Constellation data

Abstract

Photometric time series of the $\gamma$ Dor star 43 Cyg obtained with the BRITE-Constellation nano-satellites allow us to study its pulsational properties in detail and to constrain its interior structure. We aim to find a g-mode period spacing pattern that allows us to determine the near-core rotation rate of 43 Cyg and redetermine the star's fundamental atmospheric parameters and chemical composition. We conducted a frequency analysis using the 156-days long data set obtained with the BRITE-Toronto satellite and employed a suite of MESA/GYRE models to derive the mode identification, asymptotic period spacing and near-core rotation rate. We also used high-resolution, high signal-to-noise ratio spectroscopic data obtained at the 1.2m Mercator telescope with the HERMES spectrograph to redetermine the fundamental atmospheric parameters and chemical composition of 43 Cyg using the software Spectroscopy Made Easy (SME). We detected 43 intrinsic pulsation frequencies and identified 18 of them to be part of a period spacing pattern consisting of prograde dipole modes with an asymptotic period spacing $\Delta {\Pi }_{l=1}$ of $2970_{-570}^{+700}\mathrm{s}$. The near-core rotation rate was determined to be $f_{\mathrm{rot}}=0.56_{-0.14}^{+0.12}{\mathrm{d}}^{-1}$. The atmosphere of 43 Cyg shows solar chemical composition at an effective temperature of 7150 $\pm$ 150 K, a log g of 4.2 $\pm$ 0.6 dex and a projected rotational velocity, $v\sin i$, of 44 $\pm$ 4 kms${}^{-1}$. The morphology of the observed period spacing patterns shows indications of the presence of a significant chemical gradient in the stellar interior.

9 pages, 8 figures, accepted by A&A

References in corpus (13)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
• Asteroseismic measurement of surface-to-core rotation in a main sequence A star, KIC 11145123
• The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacings
• Asteroseismic measurement of slow, nearly-uniform surface-to-core rotation in the main sequence F star KIC 9244992
• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• A new asteroseismic diagnostic for internal rotation in $\gamma$ Doradus stars
• A detection threshold in the amplitude spectra calculated from Kepler data obtained during K2 mission
• Detecting non-uniform period spacings in the Kepler photometry of gamma Doradus stars: methodology and case studies
• The BRITE Constellation nanosatellite mission: Testing, commissioning and operations
• BRITE-Constellation: Data processing and photometry
• Search for exoplanets around pulsating stars of A--F type in Kepler Short Cadence data and the case of KIC 8197761
• Period spacing of gravity modes strongly affected by rotation. Going beyond the traditional approximation

Cited by in corpus (9)

• Rotation of the convective core in $\gamma$ Dor stars measured by dips in period spacings of g modes coupled with inertial modes
• Revisiting the pulsational characteristics of the exoplanet host star $\beta$ Pictoris
• Astrophysical properties of 15062 Gaia DR3 gravity-mode pulsators: pulsation amplitudes, rotation, and spectral line broadening
• Tango of celestial dancers: A sample of detached eclipsing binary systems containing g-mode pulsating components. A case study of KIC9850387
• Pulsational instability of pre-main sequence models from accreting protostars. I. Constraining the input physics for accretion with spectroscopic parameters and stellar pulsations
• beta Cas: the first delta Scuti star with a dynamo magnetic field
• Backtracing the internal rotation history of the $\beta$ Cep star HD 129929
• Space Photometry with BRITE-Constellation
• The near-core rotation of HD 112429: a gamma Doradus star with TESS photometry and legacy spectroscopy