Periodic variable A-F spectral type stars in the northern TESS continuous viewing zone

Abstract

The goal of our study is to provide a reliable classification of variability of A-F stars brighter than 11 mag located in the northern TESS continuous viewing zone. We also aim at thorough discussion about issues in the classification related to the data characteristics and the issues arising from the similar light curve shape generated by different physical mechanisms. We used TESS long- and short-cadence photometric data and corresponding Fourier transform to classify the variability type of the stars. We present a clear and concise classification system that is demonstrated on many examples. We found clear signs of variability in 3025 of 5923 studied stars (51 %). For 1813 of these 3025 stars, we provide a classification. From the classified stars, 64.5 % are pulsating stars of GDOR and DSCT types and their hybrids. We realised that the long- and short-cadence PDCSAP data can differ significantly not only in amplitudes but also in the content of instrumental/data reduction artifacts making the long-cadence data less reliable. We identified a new group of stars showing stable light curves and characteristic frequency spectra pattern (8.5 % of the classified stars). According to the position in the Hertzsprung-Russell diagram, these stars are likely GDOR stars but are about 200 K cooler than GDORs on average and have smaller amplitudes and longer periods in average. We show that without spectroscopic observations, it can be impossible to unambiguously distinguish between ellipsoidal variability and rotational variability. We also apply our methodology to three previous studies and found significant discrepancies in the classification. We demonstrate how difficult the classification of variable A-F stars can be when using only photometric data.

Accepted for publication in A&A, 23 pages, 17 figures, 5 tables

References in corpus (26)

• The Transiting Exoplanet Survey Satellite
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Modern stellar spectroscopy caveats
• TESS Eclipsing Binary Stars. I. Short cadence observations of 4584 eclipsing binaries in Sectors 1-26
• {\em Gaia}-derived luminosities of {\em Kepler} A/F stars and the pulsator fraction across the δ Scuti instability strip
• The first view of $\delta$ Scuti and $\gamma$ Doradus stars with the TESS mission
• The role of turbulent pressure as a coherent pulsational driving mechanism: the case of the delta Scuti star HD 187547
• Results of a Search for gamma Dor and delta Sct Stars with the Kepler Spacecraft
• The light variability of the helium strong star HD 37776 as a result of its inhomogeneous elemental surface distribution
• MOBSTER - II. Identification of rotationally variable A stars observed with \emph{TESS} in Sectors 1 to 4
• Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2
• Do A-type stars flare?
• First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
• On the first $\delta$ Sct--roAp hybrid pulsator and the stability of p and g modes in chemically peculiar A/F stars
• TESS Data for Asteroseismology (T'DA) Stellar Variability Classification Pipeline: Set-Up and Application to the Kepler Q9 Data
• Visual and ultraviolet flux variability of the bright CP star $\theta$ Aur
• Ondr}ejov echelle spectrograph, ground based support facility for exoplanet missions
• Asteroseismology of hybrid $\delta$ Scuti--$\gamma$ Doradus pulsating stars
• Global properties of the light curves of magnetic, chemically peculiar stars as a testbed for the existence of dipole-like symmetry in surface structures
• ELISa: A new tool for fast modelling of eclipsing binaries
• A spectroscopic test of the rotational modulation origin of periodic \emph{Kepler} photometric variability of A-type stars
• Rotation and spots in normal A and Am/Fm stars
• Rapidly-oscillating {\it TESS} A--F main sequence stars: are the roAp stars a distinct class?
• Ultralow-amplitude RR Lyrae Stars in M4
• Photometric signatures of corotating magnetospheres of hot stars governed by higher-order magnetic multipoles

Cited by in corpus (16)

• Confronting sparse Gaia DR3 photometry with TESS for a sample of around 60,000 OBAF-type pulsators
• Mass-ratio distribution of contact binary stars
• Age-dating the young open cluster UBC 1 with g-mode asteroseismology, gyrochronology, and isochrone fitting
• Tidally perturbed g-mode pulsations in a sample of close eclipsing binaries
• Stellar flare morphology with TESS across the main sequence
• Identifying 850 delta Scuti pulsators in a narrow Gaia colour range with TESS 10-minute full-frame images
• Stellar obliquities of eight close-in gas giant exoplanets
• Periodic variable A-F spectral type stars in the southern TESS continuous viewing zone
• Mode coupling coefficients between the convective core and radiative envelope of $\gamma$Doradus and slowly pulsating B stars
• Everything that glitters is not gold: V1315 Cas is not a dormant black hole
• Testing ultralow amplitude Cepheid candidates in the Galactic disk by TESS and Gaia
• Characterizing bright $\delta$ Scuti pulsators using TESS lightcurves
• Automated all-sky detection of γ Doradus / δ Scuti hybrids in TESS data from positive unlabelled (PU) learning
• 50 Dra: Am-type twins with additional variability in a non-eclipsing system
• Catalog of variable stars in the WD 0009+501 and GRW +708247 fields based on photometric survey data on transiting exoplanets
• Frequencies analysis of the hybrid delta Sct-gamma Dor star CoRoT-102314644