Detection of period-spacing patterns due to the gravity modes of rotating dwarfs in the TESS southern continuous viewing zone

Abstract

Context. The theory of stellar evolution presents shortcomings when confronted with asteroseismic probes of interior physical properties. The differences between observations and theory are often great because stellar models have mainly been calibrated from observables connected to the surface of stars. Period-spacing patterns caused by gravity modes are a particularly powerful asteroseismic tool that are useful for probing the near-core rotation and mixing of chemical elements in main-sequence stars with convective cores. Aims. We aim to compose a catalog of intermediate-mass stars in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone (CVZ) to reveal period-spacing patterns caused by gravity modes for use in future asteroseismic modeling. Methods. TESS full frame images (FFI) were inspected to select stars of intermediate- and high-mass using color-magnitude criteria. Light curves were extracted from custom masks per star, adopting stringent constraints on the aperture masks and contamination. The extracted light curves were subject to iterative prewhitening to detect gravity modes. We developed a method relying on the assumption that period spacings are an approximately linear function of the mode periods to build a template pattern. This template was used to extract the patterns and their uncertainties, relying on a bootstrap approach. Results. Our TESS catalog of high-quality period-spacing patterns is the first of its kind and contains 140 gravity-mode patterns in 106 γ Dor stars and two slowly pulsating B-type (SPB) stars. Half of these patterns contain seven or more measured mode periods and the longest pattern contains 20 modes. We provide the community with a convenient software tool to search for period-spacing patterns and to process the extracted light curves. Conclusions. Our catalog offers a fruitful starting point for future gravity-mode asteroseismology of rotating dwarfs with convective cores in the southern hemisphere.

Forward modelling and the quest for mode identification in rapidly rotating stars

“…Using the traditional approximation, Ouazzani et al (2017) thus defines the slope of this trend as a new observable that is directly linked to the rotation rate near the stellar core modulated by the azimuthal order m. These ridges were observed in many γDor (e.g. Bedding et al, 2015;Guo and Li, 2019;Li et al, 2020a,b;Garcia et al, 2022) and SPB stars (Pápics et al, 2017;Pedersen et al, 2021;Szewczuk et al, 2021Szewczuk et al, , 2022, with a variety of behaviors related to mixing and rotation.…”

“…Detections in both p-mode (e.g. García Hernández et al, 2015;Paparó et al, 2016a,b;García Hernández et al, 2017;Bedding et al, 2020) and g-mode pulsators (e.g Van Reeth et al, 2015;Li et al, 2020b;Pedersen et al, 2021;Garcia et al, 2022) yield estimates of the fundamental parameters and the internal physics of an ever-increasing number of stars.…”

Internal rotation and buoyancy travel time of 60 gamma Doradus stars from uninterrupted TESS light curves spanning 352 days

“…Ever more complex versions of the TAR, including the centrifugal and Lorentz forces, have been developed to allow for accurate predictions of gravito-inertial pulsation frequencies comparable with observations (Prat et al 2019(Prat et al , 2020Van Beeck et al 2020;Henneco et al 2021;Dhouib et al 2021aDhouib et al ,b, 2022. These various versions of the TAR inform us how gravitymode pulsation frequencies of dwarfs are affected by rotation and magnetism and allow us to search for such signatures in the space photometry (Van Reeth et al 2015a;Christophe et al 2018;Szewczuk et al 2021;Pedersen et al 2021;Garcia et al 2022). In terms of TESS data, Garcia et al (2022) relied on theoretical predictions to create a catalogue of 106 gravito-inertial pulsators with detected period-pacing patterns affected by rotation.…”

“…These various versions of the TAR inform us how gravitymode pulsation frequencies of dwarfs are affected by rotation and magnetism and allow us to search for such signatures in the space photometry (Van Reeth et al 2015a;Christophe et al 2018;Szewczuk et al 2021;Pedersen et al 2021;Garcia et al 2022). In terms of TESS data, Garcia et al (2022) relied on theoretical predictions to create a catalogue of 106 gravito-inertial pulsators with detected period-pacing patterns affected by rotation. This follow-up paper extracts the asteroseismic information from that catalogue with the aim to constrain the interior rotation and buoyancy travel time in those stars, based on ∼1 year of uninterrupted space photometry.…”

“…Proper mode identification in fast rotators is a challenging problem. In this paper, we use a comprehensive approach to test the likelihood of possible low-degree mode identifications in the detected period-spacing patterns found by Garcia et al (2022). The plan of the paper is as follows: Section 2 describes our methodology to determine the internal rotation and buoyancy travel time from period-spacing patterns.…”