Appendix to "Mode identification and ensemble asteroseismology of 119 β Cep stars detected by Gaia light curves and monitored by TESS".

Frequency spectra and light curves

The figures allpgs_{i}.pdf contain light curves (left) and periodograms (right) for all studied stars. The light curves show only the first available TESS sector for every star for illustrative purpose. The periodogram is based on all available TESS data. For each star, we indicate its light curve classification in the top right.

Standstill stars

standstill_notYetMentioned.pdf shows the remaining stars that display a standstill in their dominant pulsation mode not yet shown in the main text.

We also highlight the standstill star TIC 395218466, a member of an eccentric, short-period eclipsing binary. Its light curve folded against the pulsation and orbital periods and corresponding Fourier transform are shown in standstill_TIC395218466_unbinned.pdf. By taking the median of the frequencies of the orbital harmonics divided by the harmonic number, we find it has an orbital period of $2.657983\, \pm \, \,0.000041\,$d. STAR SHADOW's analysis of the timings of the eclipses (see IJspeert et al. 2024) suggests an orbital eccentricity of $0.5413\, \pm \, 0.0066$. Interestingly, the dominant pulsation frequency is only 0.0146\,d$^{-1}$ away from the tenth harmonic of the orbital frequency which might indicate that tides play a role in modifying or even exciting the pulsation. To our knowledge, no star displaying a standstill has ever been observed in an eclipsing binary, let alone on an eccentric orbit with likely tidally-modified pulsations, making TIC 395218466 an especially promising target for more detailed studies of its binary and asteroseismic properties.

In the upper left panel, the unbinned light curve is phase folded over its dominant pulsation period of 0.26433\,d. In the upper right panel, the light curve is instead folded over the orbital period of 2.657983\,d after all extracted signals but the orbital harmonics were removed. The light curve shown in this figure is not binned to a 30 minute cadence as the eclipses are more clearly defined in the unbinned light curve. The bottom panel shows its original Fourier spectrum.

Splittings

Here, we present all identified complete split multiplets of the pulsations modes of the studied β Cep stars. As seen from the frequency spectra presented above, some stars show more such multiplets that will be discussed elsewhere. 

splittings_asymmetries_{i}_train.pdf shows splittings identified in the sample of β Cep stars and used in the multicolour photometry. The connected, red markers indicate the splitting and the red markers at the top show all extracted frequencies. Information on the stars can be found in the box in each panel.

splittings_asymmetries_0_add.pdf contains additional splittings found in the sample of β Cep stars.