2022A&A...662A..58V -
Astronomy and Astrophysics, volume 662A58-58 (2022/6-1)
The near-core rotation of HD 112429. A γ Doradus star with TESS photometry and legacy spectroscopy.
VAN REETH T., DE CAT P., VAN BEECK J., PRAT V., WRIGHT D.J., LEHMANN H., CHENE A.-N., KAMBE E., YANG S.L.S., GENTILE G. and JOOS M.
Abstract (from CDS):
Context. The Transiting Exoplanet Survey Satellite (TESS) provides us with high-precision photometric observations of large numbers of bright stars over more than 70% of the entire sky, allowing us to revisit and characterise well-known stars.
Aims. We aim to conduct an asteroseismic analysis of the γ Doradus (γ Dor) star HD 112429 using both the available ground-based spectroscopy and TESS photometry, and assess the conditions required to measure the near-core rotation rate and buoyancy travel time.
Methods. We collected and reduced the available five sectors of short-cadence TESS photometry of this star, as well as 672 legacy observations from six medium- to high-resolution ground-based spectrographs. We determined the stellar pulsation frequencies from both data sets using iterative prewhitening, did asymptotic g mode modelling of the star, and investigated the corresponding spectral line profile variations using the pixel-by-pixel method.
Results. We validate the pulsation frequencies from the TESS data down to S/N >= 5.6, confirming recent reports in the literature that the classical criterion S/N >= 4 does not suffice for space-based observations. We identify the pulsations as prograde dipole g modes and r-mode pulsations, and measure a near-core rotation rate of 1.536 (3) d–1 and a buoyancy travel time Π0 of 4190 (50) s. These results are in agreement with the observed spectral line profile variations, which were qualitatively evaluated using a newly developed toy model. We establish a set of conditions that have to be fulfilled for an asymptotic asteroseismic analysis of g-mode pulsators. In the case of HD 112429, two TESS sectors of space photometry suffice.
Conclusions. Although a detailed asteroseismic modelling analysis is not viable for g-mode pulsators with only short or sparse light curves of space photometry, it is possible to determine global asteroseismic quantities for a subset of these stars. Thanks to the ongoing TESS mission, this will allow us to characterise many more stars than only those with years of data.
Abstract Copyright:
© ESO 2022
Journal keyword(s):
asteroseismology - methods: observational - stars: variables: general - stars: oscillations - stars: individual: HD 112429
VizieR on-line data:
<Available at CDS (J/A+A/662/A58): listphot.dat phot/* listsp.dat sp/*>
Simbad objects:
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