Hidden oscillations in plain sight: Identification of seismically unresolved red-giant asteroseismic binary candidates
Context. Light curves of oscillating stars provide valuable insights into the stellar interiors. In some cases, the aperture mask used to extract a light curve can record fluxes from multiple stars. When oscillations from a pair of stars are captured within a single aperture, they can be considered...
Enregistré dans:
| Auteurs principaux: | , , |
|---|---|
| Format: | Article (Journal) |
| Langue: | anglais |
| Publié: |
June 2026
|
| In: |
Astronomy and astrophysics
Year: 2026, Volume: 710, Pages: 1-20 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/202659277 |
| Accès en ligne: | Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202659277 Verlag, kostenfrei, Volltext: https://www.aanda.org/articles/aa/abs/2026/06/aa59277-26/aa59277-26.html 
|
| Notes sur l'auteur: | Jeong Yun Choi, Francisca Espinoza-Rojas, and Saskia Hekker |
| Résumé: | Context. Light curves of oscillating stars provide valuable insights into the stellar interiors. In some cases, the aperture mask used to extract a light curve can record fluxes from multiple stars. When oscillations from a pair of stars are captured within a single aperture, they can be considered as potential asteroseismic binaries (ABs). If the two stars oscillate at similar frequency ranges, the superpositioned oscillation patterns appear as if from a single star, which can lead to the derivation of inaccurate asteroseismic parameters. Aims. In this study, we investigate seismically unresolved AB candidates consisting of two red-giant stars observed by Kepler. We aim to make a direct comparison between the power density spectra (PDSs) of blended and separated oscillations from both stars in each candidate, and examine how oscillations from two stars in a PDS impact the measurement of asteroseismic and stellar parameters. Methods. We selected stars from the APOKASC3 catalog that have at least one neighboring source within 20 arcsec and show oscillations in similar frequency ranges. We focus on the systems where the light curves from each star in AB candidates are available or can be extracted with a custom mask. From these star pairs, we identified six seismically unresolved AB candidates whose PDS morphologies change noticeably across light curves extracted with different apertures. We determined asteroseismic parameters and derived masses and radii from the PDSs of both AB candidates and single stars to quantify the biases. Results. Oscillations from two stars in a single PDS cause inaccurate mode identification and bias the seismic parameters. These biases propagate into stellar properties, with mass and radii for the six AB candidates investigated here differing by up to ∼3 and ∼2 times relative to the individual stars, respectively. For the AB candidate with the most complex PDS, core properties such as period spacings and coupling factors become unreliable, with the coupling factor often being overestimated. We verified that all six AB candidates are chance alignments. Conclusions. Our results indicate that the inconsistencies in asteroseismic and stellar parameters across various studies on the stars with complex PDSs can be explained by potential seismically unresolved ABs. These findings highlight the importance of identifying and accurately accounting for such systems in asteroseismic analysis. |
|---|---|
| Description: | Online veröffentlicht: 10. Juni 2026 Gesehen am 04.09.2026 |
| Description matérielle: | Online Resource |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/202659277 |