We developed a light curve extraction method optimising the signal to noise ratio (S/N) of the dominant frequency in different numbers of pixel rings. We used principal component analysis to model and remove the background systematics. As Ast te er ro ose sei ism smo ol log ogy y o of f K Kepl eple er r SP SPB s B st ta ar rs s us usi ing ng T TE ESS SS Laura Scott Laura Scott & & Dominic Bowman Dominic Bowman email:
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[email protected] Kepler provided high-quality 4-yr light curves for many stars. This includes slowly pulsating B (SPB) stars, which were modelled by Pedersen et al. with Kepler light curve frequencies as a constraint on their modelling [1]. Many more stars are available with TESS. The question is: how do we know how accurate our results are using only a few TESS sectors? In this work, we compared results from Kepler and TESS by reanalysing a some of the Pedersen et al. [1] sample of SPBs using TESS. … and S/N (with best aperture) We can then make curves of growth to determine the optimum number of: Pixel rings for the target aperture Principal components for the background The aperture based on S/N is larger than what you might choose based on flux. KIC 7760680 sector 82 flux ... pixel ring shapes We chose SPBs from the Pedersen et al. Sample [1] which were bright, high-amplitude pulsators with no contamination from nearby stars. We used Period04 [2] to extract frequencies from light curves of 1, 2, or 3 chunks of consecutive sectors. We compared our frequencies from TESS to the frequencies included by Pedersen et al. in their Kepler period spacing patterns [1]. The fraction of the Kepler period spacing patterns which we recovered does not always increase with the number of sectors, and varies from star to star. filled symbol = modelled star We used AMiGO [3,4,5] to fit period spacing patterns for the best stars. Combined with temperatures and surface gravities, we fit the period spacing to model grids using the Mahalanobis distance [6]. MD = merit function X = best model Our results for mass, core mass and age were similar to the Kepler analyses, but with larger errors due to using the period spacing, not individual frequencies. KIC 7760680 grey band = Pedersen+21 KIC 4930889 Part of the Part of the SYMPHONY project SYMPHONY project KIC 7760680 had the best pattern; we modelled the star successfully with only 30% of the pattern compared to Pedersen et al. [1]. [1] Pedersen M. G., et al., 2021, Nature Astronomy, 5, 715 [2] Lenz P., Breger M., 2005, Communications in Asteroseismology, 146, 53 [3] Van Reeth T., Tkachenko A. Aerts C., 2016, A&A, 593, A120 [4] Van Reeth T., et al. 2018, A&A, 618, A24 [5] Van Reeth T., et al. 2022, A&A, 662,A58 [6] Aerts C., et al., 2018, 2018, ApJS, 237, 15 [7] Moravveji E., et al., 2016, ApJ, 823, 130 [8] Bowman D. M., Michielsen M., 2021, A&A, 656, A158 [9] Michielsen M., Aerts C., Bowman D. M., 2021, A&A, 650, A175 The authors gratefully acknowledge UK Research and Innovation (UKRI) in the form of a Frontier Research grant under the UK government’s ERC Horizon Europe funding guarantee (SYMPHONY; grant number: EP/Y031059/1), and a Royal Society University Research Fellowship (grant number: URF\R1\231631). Based on Scott & Bowman Based on Scott & Bowman (2025), submitted MNRAS (2025), submitted MNRAS
