Context. Classical double-mode pulsators (RR Lyrae stars and δ Cepheids) are important because of their simultaneous pulsation in low-order radial modes. This enables us to place stringent constraints on their physical parameters. Aims. We use 30 bright galactic double-mode RR Lyrae (RRd) stars to estimate their luminosities and compare these luminosities with those derived from the parallaxes of the recent data release (EDR3) of the Gaia survey. Methods. We employed pulsation and evolutionary models together with observationally determined effective temperatures to derive the basic stellar parameters. Results. When we exclude six outlying stars (e.g., those with blending issues), the RRd and Gaia luminosities correlate well. With the adopted temperature zeropoint from one of the works based on the infrared flux method, we find it necessary to increase the Gaia parallaxes by 0.02 mas to bring the RRd and Gaia luminosities into agreement. This value is consonant with those derived from studies on binary stars in the context of Gaia. We also examined the resulting period-luminosity-metallicity (PLZ) relation in the 2MASS K band as follows from the RRd parameters. This leads to the verification of two independently derived other PLZs. No significant zeropoint differences are found. Furthermore, the predicted K absolute magnitudes agree within σ = 0.005 − 0.01 mag.

We combine observed metallicity, optical, and infrared magnitudes with evolutionary and pulsation models to derive average luminosities for 156 single-mode RR Lyrae stars. These luminosities are compared with those obtained from the Gaia EDR3 parallaxes and are found to be in excellent agreement with the high accuracy subsample (62 stars, with relative parallax errors of less than 2%). With the temperature and metallicity scale used, no parallax shift seems to be necessary when α-enhanced evolutionary models are employed. Some 10% of the sample shows curious “distance keeping” between the evolutionary and pulsation models. The cause of this behavior is not clear at this moment but can be cured by an excessive increase in the reddening.

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Context. Thermal emission from extrasolar planets makes it possible to study important physical processes in their atmospheres and derive more precise orbital elements. Aims. By using new near-infrared (NIR) and optical data, we examine how these data constrain the orbital eccentricity and the thermal properties of the planet atmosphere. Methods. The full light curves acquired by the TESS satellite from two sectors are used to put an upper limit on the amplitude of the phase variation of the planet and estimate the occultation depth. Two previously published observations and one followup observation (published herein) in the 2MASS K (Ks) band are employed to derive a more precise occultation light curve in this NIR waveband. Results. The merged occultation light curve in the Ks band comprises 4515 data points. The data confirm the results of the earlier eccentricity estimates, suggesting a circular orbit of: e = 0.005 ± 0.015. The high value of the flux depression of (2.70 ± 0.14) ppt in the Ks band excludes simple black body emission at the 10σ level and also disagrees with current atmospheric models at the (4–7)σ level. From analysis of the TESS data, in the visual band we find tentative evidence for a near-noise-level detection of the secondary eclipse, and place constraints on the associated amplitude of the phase variation of the planet. A formal box fit yields an occultation depth of (0.157 ± 0.056) ppt. This implies a relatively high geometric albedo of Ag = 0.43 ± 0.15 for fully efficient atmospheric circulation and Ag = 0.29 ± 0.15 for no circulation at all. No preference can be seen for either the oxygen-enhanced or the carbon-enhanced atmosphere models.