Context.
The Transiting Exoplanet Survey Satellite (TESS) mission has provided photometric light curves for stars across nearly the entire sky. This allows for the application of asteroseismology to ...a pool of potential solar-like oscillators that is unprecedented in size.
Aims.
We aim to produce a catalogue of solar-like oscillators observed by TESS in the 120-s and 20-s cadence modes. The catalogue is intended to highlight stars oscillating at frequencies above the TESS 30-min cadence Nyquist frequency with the purpose of encompassing the main-sequence and subgiant evolutionary phases. We aim to provide estimates for the global asteroseismic parameters
v
max
and ∆
v
.
Methods.
We applied a new probabilistic detection algorithm to the 120-s and 20-s light curves of over 250 000 stars. This algorithm flags targets that show characteristic signatures of solar-like oscillations. We manually vetted the resulting list of targets to confirm the presence of solar-like oscillations. Using the probability densities computed by the algorithm, we measured the global asteroseismic parameters
v
max
and ∆
v
.
Results.
We produce a catalogue of 4177 solar-like oscillators, reporting ∆
v
and
v
max
for 98% of the total star count. The asteroseismic data reveal a vast coverage of the Hertzsprung-Russell diagram, populating the red giant branch, the subgiant regime, and extending towards the main sequence.
Conclusions.
A crossmatch with external catalogues shows that 25 of the detected solar-like oscillators are a component of a spectroscopic binary, and 28 are confirmed planet host stars. These results provide the potential for precise, independent asteroseismic constraints on these and any additional TESS targets of interest.
Abstract
The launch of NASA’s Kepler space telescope in 2009 revolutionized the quality and quantity of observational data available for asteroseismic analysis. While Kepler was able to detect ...solar-like oscillations in hundreds of main-sequence and subgiant stars, the Transiting Exoplanet Survey Satellite is now making similar observations for thousands of the brightest stars in the sky. The Asteroseismic Modeling Portal (AMP) is an automated and objective stellar model-fitting pipeline for asteroseismic data, which was originally developed to use models from the Aarhus Stellar Evolution Code. We briefly summarize an updated version of the AMP pipeline that uses Modules for Experiments in Stellar Astrophysics, and we present initial modeling results for the Sun and several solar analogs to validate the precision and accuracy of the inferred stellar properties.
We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA’s Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be ...of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the MINERVA-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of M(P) = 0.138 ± 0.023 M(J) (43.9 ± 7.3 Mꚛ), a radius of R(P) = 0.639 ± 0.013 R(J) (7.16 ± 0.15 Rꚛ), bulk density of 0.65 (+0.12,−0.11) (cgs), and period 18.38818 (+0.00085,−0.00084) days. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M⁎ = 1.390 ± 0.046 M(sun), R⁎ = 1.888 ± 0.033 R(sun), T(eff) = 6075 ± 90 K, and 𝜈sin 𝑖 = 11.3 ± 0.5 km/s. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.
The KEYSTONE project aims to enhance our understanding of solar-like oscillators by delivering a catalogue of global asteroseismic parameters ( and for 173 stars, comprising mainly dwarfs and ...subgiants, observed by the K2 mission in its short-cadence mode during campaigns 6-19. We derive atmospheric parameters and luminosities using spectroscopic data from TRES, astrometric data from Gaia and the infrared flux method (IRFM) for a comprehensive stellar characterisation. Asteroseismic parameters are robustly extracted using three independent methods, complemented by an iterative refinement of the spectroscopic analyses using seismic values to enhance parameter accuracy. Our analysis identifies new detections of solar-like oscillations in 159 stars, providing an important complement to already published results from previous campaigns. The catalogue provides homogeneously derived atmospheric parameters and luminosities for the majority of the sample. Comparison between spectroscopic and those obtained from the IRFM demonstrates excellent agreement. The iterative approach to spectroscopic analysis significantly enhances the accuracy of the stellar properties derived.
Since the onset of the "space revolution" of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The ...launch of the NASA Transiting Exoplanet Survey Satellite (TESS) mission has enabled seismic-based inferences to go full sky-providing a clear advantage for large ensemble studies of the different Milky Way components. Here we demonstrate its potential for investigating the Galaxy by carrying out the first asteroseismic ensemble study of red giant stars observed by TESS. We use a sample of 25 stars for which we measure their global asteroseimic observables and estimate their fundamental stellar properties, such as radius, mass, and age. Significant improvements are seen in the uncertainties of our estimates when combining seismic observables from TESS with astrometric measurements from the Gaia mission compared to when the seismology and astrometry are applied separately. Specifically, when combined we show that stellar radii can be determined to a precision of a few percent, masses to 5%-10%, and ages to the 20% level. This is comparable to the precision typically obtained using end-of-mission Kepler data.
Abstract
We present an analysis of the first 20 second cadence light curves obtained by the TESS space telescope during its extended mission. We find improved precision of 20 second data compared to ...2 minute data for bright stars when binned to the same cadence (≈10%–25% better for
T
≲ 8 mag, reaching equal precision at
T
≈ 13 mag), consistent with pre-flight expectations based on differences in cosmic-ray mitigation algorithms. We present two results enabled by this improvement. First, we use 20 second data to detect oscillations in three solar analogs (
γ
Pav,
ζ
Tuc, and
π
Men) and use asteroseismology to measure their radii, masses, densities, and ages to ≈1%, ≈3%, ≈1%, and ≈20% respectively, including systematic errors. Combining our asteroseismic ages with chromospheric activity measurements, we find evidence that the spread in the activity–age relation is linked to stellar mass and thus the depth of the convection zone. Second, we combine 20 second data and published radial velocities to recharacterize
π
Men c, which is now the closest transiting exoplanet for which detailed asteroseismology of the host star is possible. We show that
π
Men c is located at the upper edge of the planet radius valley for its orbital period, confirming that it has likely retained a volatile atmosphere and that the “asteroseismic radius valley” remains devoid of planets. Our analysis favors a low eccentricity for
π
Men c (<0.1 at 68% confidence), suggesting efficient tidal dissipation (
Q
/
k
2,1
≲ 2400) if it formed via high-eccentricity migration. Combined, these early results demonstrate the strong potential of TESS 20 second cadence data for stellar astrophysics and exoplanet science.
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