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First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances

Molnár, L. and Bódi, A. and Pál, András and Bhardwaj, A. and Hambsch, F.J. and Benko, J. M. and Derekas, A. and Ebadi, M. and Joyce, M. and Hasanzadeh, A. and Kolenberg, K. and Lund, M.B. and Nemec, J.M. and Netzel, H. and Ngeow, C.C. and Pepper, J. and Plachy, E. and Prudil, Z. and Siverd, R. J. and Skarka, M. and Smolec, R. and Sódor, Á. and Sylla, S. and Szabó, Pál and Szabó, R. and Kjeldsen, H. and Christensen-Dalsgaard, J. and Ricker, G.R. (2021) First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances. Astrophysical Journal Supplement Series. (In Press)

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Abstract

The TESS space telescope is collecting continuous, high-precision optical photometry of stars throughout the sky, including thousands of RR Lyrae stars. In this paper, we present results for an initial sample of 118 nearby RR Lyrae stars observed in TESS Sectors 1 and 2. We use differential-image photometry to generate light curves and analyse their mode content and modulation properties. We combine accurate light curve parameters from TESS with parallax and color information from the Gaia mission to create a comprehensive classification scheme. We build a clean sample, preserving RR Lyrae stars with unusual light curve shapes, while separating other types of pulsating stars. We find that a large fraction of RR Lyrae stars exhibit various low-amplitude modes, but the distribution of those modes is markedly different from those of the bulge stars. This suggests that differences in physical parameters have an observable effect on the excitation of extra modes, potentially offering a way to uncover the origins of these signals. However, mode identification is hindered by uncertainties when identifying the true pulsation frequencies of the extra modes. We compare mode amplitude ratios in classical double-mode stars to stars with extra modes at low amplitudes and find that they separate into two distinct groups. Finally, we find a high percentage of modulated stars among the fundamental-mode pulsators, but also find that at least 28% of them do not exhibit modulation, confirming that a significant fraction of stars lack the Blazhko effect.

Item Type: Article
Subjects: Q Science / természettudomány > QB Astronomy, Astrophysics / csillagászat, asztrofizika
Depositing User: Dr. Aliz Derekas
Date Deposited: 28 Sep 2021 14:42
Last Modified: 31 Dec 2023 00:16
URI: http://real.mtak.hu/id/eprint/131254

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