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

Molnár, László; Bódi, Attila; Pál, András; Bhardwaj, Anupam; Hambsch, Franz-Josef; Benkő, József M.; Derekas, Aliz; Ebadi, Mohammad; Joyce, Meridith; Hasanzadeh, Amir; Kolenberg, Katrien; Lund, Michael B.; Nemec, James M.; Netzel, Henryka; Ngeow, Chow-Choong; Pepper, Joshua; Plachy, Emese; Prudil, Zdeněk; Siverd, Robert J.; Skarka, Marek; Smolec, Radosław; Sódor, Ádám; Sylla, Salma; Szabó, Pál; Szabó, Róbert; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen; Ricker, George R.

doi:10.48550/arxiv.2109.07329

Cited by 4 publications

(4 citation statements)

References 129 publications

(200 reference statements)

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“…Color-magnitude diagrams of globular clusters M3 and NGC 6362 suggest that RR 0.61 tend to avoid the hottest (bluest) part of the diagrams (Jurcsik et al 2015;Smolec et al 2017b). Similar trend was noted for the TESS RR 0.61 stars (Molnár et al 2021). Thus, observations indicate that RR 0.61 phenomenon, while widespread, is not ubiquitous.…”

Section: The Incidence Rates Of Rr 061 Starssupporting

confidence: 63%

“…Molnár et al (2015) analyzed test K2 data for RR Lyrae stars in a field in Pisces and obtained incidence rate of RR 0.61 stars of 75 per cent. First results on the RR Lyrae stars observed in the TESS mission provided incidence rate of 65 per cent (Molnár et al 2021). General conclusion that can be drawn from these results is that the better the quality of the photometry, the higher the incidence rate.…”

Section: The Incidence Rates Of Rr 061 Starsmentioning

confidence: 95%

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Asteroseismology of RR Lyrae stars with non-radial modes

Netzel¹,

Smolec²

2022

Monthly Notices of the Royal Astronomical Society

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The additional signals observed in the frequency spectra of the first-overtone RR Lyrae stars, which form a period ratio around 0.61 with the period of the first overtone, are a common phenomenon for RRc and RRd stars, as well as for first-overtone classical Cepheids. The recently proposed model explains these signals as harmonics of non-radial modes of degrees 8 or 9 in the case of RR Lyrae stars and 7, 8, or 9 in the case of classical Cepheids. We selected at least triple-mode RR Lyrae stars pulsating in radial and non-radial modes for asteroseismic modelling. We assume the identification of the non-radial modes as predicted by the model. We calculated a dense grid of models for RR Lyrae stars using envelope pulsation code. By matching first-overtone period and period ratios, we obtained physical parameters for the selected sample of triple-mode stars. It is the very first attempt of modelling RR Lyrae stars with non-radial modes. We compared our results with predictions of stellar evolution theory, which resulted in a mass discrepancy more noticeable for long-period stars: Pulsation masses seem higher than evolutionary masses. We compared metallicity estimates for RRc stars from a modelled sample with metallicities determined spectroscopically for a sample of RRc stars in the solar neighbourhood: Both distributions are consistent.

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Section: The Incidence Rates Of Rr 061 Starssupporting

confidence: 63%

Section: The Incidence Rates Of Rr 061 Starsmentioning

confidence: 95%

Asteroseismology of RR Lyrae stars with non-radial modes

Netzel¹,

Smolec²

2022

Monthly Notices of the Royal Astronomical Society

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“…The error bars on the colors are large, and the main source of the error is the reddening, and dust map inaccuracies. For stars with apparent magnitudes above 13-14 mag Molnár et al (2021) the CMD is reliable in distinguishing between fundamental mode and overtone pulsation within one type of pulsating stars, but it is not too good for determining variable star classes (RRL vs ACEP vs DCEP vs T2C).…”

Section: Color-magnitude Diagram From Gaia Datamentioning

confidence: 99%

Type II and anomalous Cepheids in the Kepler K2 mission

Jurković

Plachy

Molnár

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We present the results of the analysis of Type II and anomalous Cepheids using the data from the Kepler K2 mission. The precise light curves of these pulsating variable stars are the key to study the details of their pulsation, such as the period-doubling effect or the presence of additional modes. We applied the Automated Extended Aperture Photometry (autoEAP) to obtain the light curves of the targeted variable stars which were observed. The light curves were Fourier analyzed. We investigated twelve stars observed by the K2 mission, seven Type II and five anomalous Cepheids. Among the Type II Cepheids EPIC 210622262 shows period-doubling, and four stars have modulation present in their light curves which are different from the period-doubling effect. We calculated the high-order Fourier parameters for the short-period Cepheids. We also determined physical parameters by fitting model atmospheres to the spectral energy distributions. The determined distances using the parallaxes measured by the Gaia space telescope have limited precision below 16 mag for these types of pulsating stars, regardless if the inverse method is used or the statistical method to calculate the distances. The BaSTI evolutionary models were compared to the luminosities and effective temperatures. Most of the Type II Cepheids are modeled with low metallicity models, but for a few of them solar-like metallicity ([Fe/H]=0.06) model is required. The anomalous Cepheids are compared to low-metallicity single stellar models. We do not see signs of binarity among our sample stars.

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“…Up to now, the best applications in RR Lyrae stars study have relied dominantly on classical ground-based data sets (Alcock et al (2003) and Soszyński et al (2019)), improved progressively by use of space telescopes such as CoRoT (Auvergne et al (2009) and Chadid ( 2012)), Kepler (Gilliland et al (2010), Benkő et al (2014) and Molnár et al (2015) ) and TESS (Molnár et al (2021)), and accomplished by implementing a new way, Antarctica polar observations with PAIX long uninterrupted and continuous precision observations over 150 days from the ground, 1 polar night, and without the regular interruptions imposed by the earth rotation (Chadid & Vernin (2019) and Chadid et al (2014)).…”

Section: Introductionmentioning

confidence: 99%

Detection of Gravity Modes in RR Lyrae Stars

Chadid

2022

Preprint

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We report the detection of gravity modes in RR Lyrae stars. Thanks to PAIX, the first Antarctica polar photometer. Unprecedented and uninterrupted U BV RI time-series photometric ground-based data are collected during 150 days from the highest plateau of Antarctica. PAIX light curve analyses reveal an even richer power spectrum with mixed modes in RR Lyrae stars. A nonlinear nature of several dominant peaks, showing lower and higher frequencies, occur around the dominant fundamental radial pressure mode. These lower frequencies and harmonics linearly interact with the dominant fundamental radial pressure mode and its second and third overtone pressure modes as well. Halfinteger frequencies are also detected, likewise side peak structures demonstrating that HH puppis is a bona-fide Blazhko star. Fourier correlations are used to derive underlying physical characteristics for HH puppis. The most striking finding is the direct detection of gravity waves. We interpret the excitation mechanism of gravity waves in RR Lyrae stars by the penetrative convection driving mechanism. We demonstrate that RR Lyrae stars pulsation is excited by several distinct mechanisms, and hence RR Lyrae stars are simultaneously g modes and p modes pulsators. Our discoveries make RR Lyrae stars very challenging stellar objects, and provide their potential to undergo at the same time g modes and p modes towards an advancement of theory of stellar evolution and a better understanding of the Universe.

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

Cited by 4 publications

References 129 publications

Asteroseismology of RR Lyrae stars with non-radial modes

Asteroseismology of RR Lyrae stars with non-radial modes

Type II and anomalous Cepheids in the Kepler K2 mission

Detection of Gravity Modes in RR Lyrae Stars

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