Updating the theoretical tidal evolution constants: Apsidal motion and the moment of inertia

Claret, A.

doi:10.1051/0004-6361/201936007

Cited by 33 publications

(20 citation statements)

References 29 publications

(31 reference statements)

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“…The masses of both components were adopted from Albrecht et al (2009). The limb-darkening coefficients and the gravitydarkening coefficient were taken from Claret (2017). The rotation period of the primary star was determined in Section 2.…”

Section: Synthesismentioning

confidence: 99%

DI Herculis Revisited: Starspots, Gravity Darkening, and 3-D Obliquities

Liang,

Winn,

Albrecht

2022

Preprint

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DI Herculis is an eclipsing binary famous for a longstanding disagreement between theory and observation of the apsidal precession rate, which was resolved when both stars were found to be severely misaligned with the orbit. We used data from the Transiting Exoplanet Survey Satellite (TESS) to refine our knowledge of the stellar obliquities and sharpen the comparison between the observed and theoretical precession rates. The TESS data show variations with a 1.07-day period, which we interpret as rotational modulation from starspots on the primary star. This interpretation is supported by the detection of photometric anomalies during primary eclipses consistent with starspot crossings. The secondary eclipse light curve shows a repeatable asymmetry which we interpret as an effect of gravity darkening. By combining the TESS data with previously obtained data, we determined the three-dimensional spin directions of both stars. Using this information, the updated value of the theoretical apsidal precession rate (including the effects of tides, rotation, and general relativity) is 1.35 +0.58 −0.50 arcsec/cycle. The updated value of the observed rate (after including new TESS eclipse times) is 1.41 +0.39 −0.28 arcsec/cycle. Given the agreement between the observed and theoretical values, we fitted all the relevant data simultaneously assuming the theory is correct. This allowed us to place tighter constraints on the stellar obliquities, which are 75 +3 −3 and 80 +3 −3 degrees for the primary and secondary stars, respectively.

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Section: Synthesismentioning

confidence: 99%

DI Herculis Revisited: Starspots, Gravity Darkening, and 3-D Obliquities

Liang,

Winn,

Albrecht

2022

Preprint

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“…With differing values of 𝑘 being employed, there is no established relationship to confidently say whether a contact binary system is unstable regardless of its measured mass ratio. Rucinski (1988) and Claret (2019) calculated 𝑘 for stars of different masses and radii (non-rotating), showing that there is considerable variation in 𝑘 with changing stellar mass. In both cases, stars with mass > 0.8𝑀 were modelled and no rotational or tidal effects were included.…”

Section: Instability Mass Ratio Of Contact Binary Systemsmentioning

confidence: 99%

ZZ Piscis Austrinus (ZZ PsA): a bright red nova progenitor and the instability mass ratio of contact binary stars

Wadhwa

Horta

Filipović

et al. 2020

Monthly Notices of the Royal Astronomical Society

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ZZ PsA is a neglected bright southern contact binary system with maximum V magnitude of 9.26. We present the first multi-band photometric analysis and find the system to be in deep contact (>95%) with an extremely low mass ratio of 0.078. The primary has a mass of 1.213 M⊙ in keeping with its reported spectral class of F6. In order to determine if ZZ PsA is a merger candidate we outline the current status regarding the instability mass ratio and develop new relationship linking the mass of the primary to the instability mass ratio of the system and the degree of contact. We find that ZZ PsA along with two other examples from the literature to be merger candidates while an additional three require further observations to be confirmed as potential merger candidates.

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“…In all cases where radii were not provided explicitly, we estimated them using aforementioned isochrones. The apsidal motion constant k 2 was recently re-calculated by Claret (2019). For wide range of masses (2 -30 M ) at the main sequence log(k 2 ) ranges between −3.2 and −1.7.…”

Section: Discussionmentioning

confidence: 99%

Massive heartbeat stars from TESS. I. TESS sectors 1-16

Kołaczek-Szymański,

Pigulski,

Michalska

et al. 2020

Preprint

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Context. Heartbeat stars are eccentric binaries exhibiting characteristic shape of brightness changes during periastron passage caused primarily by variable tidal distortion of the components. Variable tidal potential can drive tidally excited oscillations (TEOs), which are usually gravity modes. Studies of heartbeat stars and TEOs open a new possibility to probe interiors of massive stars. There are only a few massive (masses of components 2 M ) systems of this type known. Aims. Using TESS data from the first 16 sectors, we searched for new massive heartbeat stars and TEOs using a sample of over 300 eccentric spectroscopic binaries. Methods. We analysed TESS 2-min and 30-min cadence data. Then, we fitted Kumar's analytical model to the light curves of stars showing heartbeats and performed times-series analysis of the residuals searching for TEOs and periodic intrinsic variability. Results. We found 20 massive heartbeat systems, of which seven show TEOs. The TEOs occur at harmonics of orbital frequencies in the range between 3 and 36, with the median value equal to 9, lower than those in known Kepler systems with TEOs. The most massive system in this sample is the quadruple star HD 5980, a member of Small Magellanic Cloud. With the total mass of ∼150 M it is the most massive system showing a heartbeat. Six stars in the sample of the new heartbeat stars are eclipsing. Comparison of the parameters derived from fitting Kumar's model and from light-curve modelling shows that Kumar's model does not provide reliable parameters. In other words, orbital parameters can be reliably derived from fitting heartbeat light curves only if model includes all proximity effects. Finally, intrinsic pulsations of β Cep, SPB, δ Sct, and γ Dor-type were found in nine heartbeat systems. This opens an interesting possibility of studies of pulsation-binarity interaction and the co-existence of forced and self-excited oscillations.

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Updating the theoretical tidal evolution constants: Apsidal motion and the moment of inertia

Cited by 33 publications

References 29 publications

DI Herculis Revisited: Starspots, Gravity Darkening, and 3-D Obliquities

DI Herculis Revisited: Starspots, Gravity Darkening, and 3-D Obliquities

ZZ Piscis Austrinus (ZZ PsA): a bright red nova progenitor and the instability mass ratio of contact binary stars

Massive heartbeat stars from TESS. I. TESS sectors 1-16

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