The Delta Scuti star 38 Eri from the ground and from space
arXiv:1804.01769 · doi:10.1093/mnras/sty885
Abstract
We present and discuss the pulsational characteristics of the Delta Scuti star 38 Eri from photometric data obtained at two widely spaced epochs, partly from the ground (1998) and partly from space (MOST, 2011). We found 18 frequencies resolving the discrepancy among the previously published frequencies. Some of the frequencies appeared with different relative amplitudes at two epochs, however, we carried out investigation for amplitude variability for only the MOST data. Amplitude variability was found for one of three frequencies that satisfy the necessary frequency criteria for linear-combination or resonant-mode coupling. Checking the criteria of beating and resonant-mode coupling we excluded them as possible reason for amplitude variability. The two recently developed methods of rotational-splitting and sequence-search were applied to find regular spacings based only on frequencies. Doublets or incomplete multiplets with l=1, 2 and 3 were found in the rotational splitting search. In the sequence search method we identified four sequences. The averaged spacing, probably a combination of the large separation and the rotational frequency, is 1.724+/-0.092 d-1. Using the spacing and the scaling relation gcm was derived. The shift of the sequences proved to be the integer multiple of the rotational splitting spacing. Using the precise MOST frequencies and multi-colour photometry in a hybrid way, we identified four modes with l=1, two modes with l=2, two modes with l=3, and two modes as l=0 radial modes.
arXiv comment20 pages, 10 figures, accepted for publication in MNRAS
References in corpus (38)
- Modules for Experiments in Stellar Astrophysics (MESA)
- Validation of the new Hipparcos reduction
- Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
- Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
- Kepler Mission Design, Realized Photometric Performance, and Early Science
- Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
- HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope
- Amplitude modulation in Sct stars: statistics from an ensemble study of Kepler targets
- Fundamental parameters and infrared excesses of Tycho-Gaia stars
- Acoustic oscillations in rapidly rotating polytropic stars I. Effects of the centrifugal distortion
- Asymptotic analysis of high-frequency acoustic modes in rapidly rotating stars
- Asteroseismic analysis of the CoRoT δ-Scuti star HD174936
- Constraints on stellar convection from multi-colour photometry of Delta Scuti stars
- Regular patterns in the acoustic spectrum of rapidly rotating stars
- Measuring mean densities of delta Scuti stars with asteroseismology. Theoretical properties of large separations using TOUCAN
- An in-depth study of HD 174966 with CoRoT photometry and HARPS spectroscopy. Large separation as a new observable for δSct stars
- Evidence of resonant mode coupling and the relationship between low and high frequencies in a rapidly rotating A star
- Non-adiabatic theoretical observables in Delta Scuti stars
- Close frequency pairs in Delta Scuti stars
- Toward mode selection in Delta Scuti stars: Regularities in observed and theoretical frequency spectra
- The role of rotation on Petersen Diagrams. The period ratios
- Precise surface gravities of Scuti stars from asteroseismology
- Discovery of the new slowly pulsating B star HD 163830 (B5II/III) from MOST spacebased photometry
- Unexpected series of regular frequency spacing of delta Scuti stars in the non-asymptotic regime -- II. Sample -- echelle diagrams and rotation
- Mode identification in rapidly rotating stars
- Frequency regularities of acoustic modes and multi-colour mode identification in rapidly rotating stars
- The role of rotation on Petersen Diagrams. II The influence of near-degeneracy
- Unexpected series of regular frequency spacing of delta Scuti stars in the non-asymptotic regime -- I. The methodology
- MIARMA: An information preserving method for filling gaps in time series. Application to CoRoT light curves
- P-modes in rapidly rotating stars -- looking for regular patterns in synthetic asymptotic spectra
- Semi-empirical seismic relations of A-F stars from CoRoT and Kepler legacy data
- Short time-scale frequency and amplitude variations in the pulsations of an roAp star: HD 217522
- CoRoT 102749568: mode identification in a delta Scuti star based on regular spacings
- Asteroseismology of the Scuti star HD 50844
- Effect of convective outer layers modeling on non-adiabatic seismic observables of delta Scuti stars
- Nonradial and radial period changes of the Delta Scuti star 4 CVn II. Systematic behavior over 40 years
- Rotational splitting and asteroseismic modelling of the delta Scuti star EE Camelopardalis
- Exploring the helium core of the delta Scuti star CoRoT 102749568 with asteroseismology