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The first view of δ Scuti and γ Doradus stars with the TESS mission

V. Antoci, M. S. Cunha, D. M. Bowman, S. J. Murphy, D. W. Kurtz, T. R. Bedding, C. C. Borre, S. Christophe, J. Daszyńska-Daszkiewicz, L. Fox-Machado, A. García Hernández, H. Ghasemi, R. Handberg, H. Hansen, A. Hasanzadeh, G. Houdek, C. Johnston, A. B. Justesen, F. Kahraman Alicavus, K. Kotysz, D. W. Latham, Matthews J. M., J. Mønster, E. Niemczura, E. Paunzen, J. P. Sánchez Arias, A. Pigulski, J. Pepper, T. Richey-Yowell, H. Safari, S. Seager, B. Smalley, T. Shutt, A. Sódor, J.-C. Suárez, A. Tkachenko, T. Wu, K. Zwintz, S. Barceló Forteza, E. Brunsden, Z. Bognár, D. L. Buzasi, S. Chowdhury, P. De Cat, J. A. Evans, Z. Guo, J. A. Guzik, N. Jevtic, P. Lampens, M. Lares-Martiz, C. Lovekin, G. Li, G. M. Mirouh, D. E. Mkrtichian, M. J. P. F. G. Monteiro, J. M. Nemec, R.-M. Ouazzani, J. Pascual-Granado, D. R. Reese, M. Rieutord, J. R. Rodón, M. Skarka, P. Sowicka, I. Stateva, R. Szabó, W. W. Weiss

Abstract
We present the first asteroseismic results for δ Scuti and γ Doradus stars observed in Sectors 1 and 2 of the TESS mission. We utilize the 2-min cadence TESS data for a sample of 117 stars to classify their behaviour regarding variability and place them in the Hertzsprung–Russell diagram using Gaia DR2 data. Included within our sample are the eponymous members of two pulsator classes, γ Doradus and SX Phoenicis. Our sample of pulsating intermediate-mass stars observed by TESS also allows us to confront theoretical models of pulsation driving in the classical instability strip for the first time and show that mixing processes in the outer envelope play an important role. We derive an empirical estimate of 74 per cent for the relative amplitude suppression factor as a result of the redder TESS passband compared to the Kepler mission using a pulsating eclipsing binary system. Furthermore, our sample contains many high-frequency pulsators, allowing us to probe the frequency variability of hot young δ Scuti stars, which were lacking in the Kepler mission data set, and identify promising targets for future asteroseismic modelling. The TESS data also allow us to refine the stellar parameters of SX Phoenicis, which is believed to be a blue straggler.

Keywords
asteroseismology; techniques: photometric; stars: chemically peculiar; stars: interiors; stars: variables: δ Scuti; Astrophysics - Solar and Stellar Astrophysics E-Print

Monthly Notices of the Royal Astronomical Society
Volume 490, Issue 3, Page 4040
2019 October

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia