Orbital circularization of close binary stars on the pre-main sequence

Khaliullin, Kh. F.; Khaliullina, A. I.

doi:10.1111/j.1365-2966.2010.17878.x

Cited by 23 publications

(14 citation statements)

References 90 publications

(98 reference statements)

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“…The coupled stellar-tidal orbital evolution of binary systems has been extensively studied in the literature for systems ranging from star-star binaries (e.g. Huang 1966;Mestel 1968;van't Veer & Maceroni 1988;Zahn & Bouchet 1989;Li & Wickramasinghe 1998;Khaliullin & Khaliullina 2011) to star-planet binaries (e.g. Dobbs-Dixon et al 2004;Barker & Ogilvie 2009;Lanza & Mathis 2016) to even star-compact object binaries (e.g.…”

Section: Coupled Stellar-tidal Evolutionmentioning

confidence: 99%

On the Lack of Circumbinary Planets Orbiting Isolated Binary Stars

Fleming

Barnes

Graham

et al. 2018

ApJ

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We outline a mechanism that explains the observed lack of circumbinary planets (CBPs) via coupled stellar-tidal evolution of isolated binary stars. Tidal forces between low-mass, short-period binary stars on the pre-main sequence slow the stellar rotations, transferring rotational angular momentum to the orbit as the stars approach the tidally locked state. This transfer increases the binary orbital period, expanding the region of dynamical instability around the binary, and destabilizing CBPs that tend to preferentially orbit just beyond the initial dynamical stability limit. After the stars tidally lock, we find that angular momentum loss due to magnetic braking can significantly shrink the binary orbit, and hence the region of dynamical stability, over time impacting where surviving CBPs are observed relative to the boundary. We perform simulations over a wide range of parameter space and find that the expansion of the instability region occurs for most plausible initial conditions and that in some cases, the stability semi-major axis doubles from its initial value. We examine the dynamical and observable consequences of a CBP falling within the dynamical instability limit by running N-body simulations of circumbinary planetary systems and find that typically, at least one planet is ejected from the system. We apply our theory to the shortest period Kepler binary that possesses a CBP, Kepler-47, and find that its existence is consistent with our model. Under conservative assumptions, we find that coupled stellar-tidal evolution of pre-main sequence binary stars removes at least one close-in CBP in 87% of multi-planet circumbinary systems.

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Section: Coupled Stellar-tidal Evolutionmentioning

confidence: 99%

On the Lack of Circumbinary Planets Orbiting Isolated Binary Stars

Fleming

Barnes

Graham

et al. 2018

ApJ

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“…As the eclipsing components are being driven by tides toward synchronization to their orbital motion, radial contraction is changing the spin rates via conservation of angular momentum. In addition, Zahn & Bouchet (1989) and Khaliullin & Khaliullina (2011) both argue that the orbital period of Par 1802 is small enough for circularization and synchronization to occur prior to the arrival on the main sequence. As such, the assignment of P 1 as the rotational period of both eclipsing components is reasonable.…”

Section: Notesmentioning

confidence: 99%

“…Radial contraction will also enter into the angular momentum evolution through the rotational frequency (Equations (B3) and (B12)). Thus, we have added radial contraction to the CPL and CTL models, in a manner similar to that in Khaliullin & Khaliullina (2011), but note that their treatment does not include obliquity effects. D 'Antona & Mazzitelli (1997) and Baraffe et al (1998) provide from their calculations the time rate of change of the radius, dR/dt in R /Myr, for 0.4 M stars.…”

Section: Tidal Evolution and Heatingmentioning

confidence: 99%

Luminosity Discrepancy in the Equal-Mass, Pre-Main-Sequence Eclipsing Binary Par 1802: Non-Coevality or Tidal Heating?

Chew

Stassun

Prša

et al. 2011

ApJ

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Parenago 1802, a member of the ∼1 Myr Orion Nebula Cluster, is a double-lined, detached eclipsing binary in a 4.674 day orbit, with equal-mass components (M 2 /M 1 = 0.985 ± 0.029). Here we present extensive VI C JHK S light curves (LCs) spanning ∼15 yr, as well as a Keck/High Resolution Echelle Spectrometer (HIRES) optical spectrum. The LCs evince a third light source that is variable with a period of 0.73 days, and is also manifested in the high-resolution spectrum, strongly indicating the presence of a third star in the system, probably a rapidly rotating Classical T Tauri star. We incorporate this third light into our radial velocity and LC modeling of the eclipsing pair, measuring accurate masses (M 1 = 0.391 ± 0.032 and M 2 = 0.385 ± 0.032 M ), radii (R 1 = 1.73 ± 0.02 and R 2 = 1.62 ± 0.02 R ), and temperature ratio (T eff,1 /T eff,2 = 1.0924 ± 0.0017). Thus, the radii of the eclipsing stars differ by 6.9% ± 0.8%, the temperatures differ by 9.2% ± 0.2%, and consequently the luminosities differ by 62% ± 3%, despite having masses equal to within 3%. This could be indicative of an age difference of ∼3 × 10 5 yr between the two eclipsing stars, perhaps a vestige of the binary formation history. We find that the eclipsing pair is in an orbit that has not yet fully circularized, e = 0.0166 ± 0.003. In addition, we measure the rotation rate of the eclipsing stars to be 4.629 ± 0.006 days; they rotate slightly faster than their 4.674 day orbit. The non-zero eccentricity and super-synchronous rotation suggest that the eclipsing pair should be tidally interacting, so we calculate the tidal history of the system according to different tidal evolution theories. We find that tidal heating effects can explain the observed luminosity difference of the eclipsing pair, providing an alternative to the previously suggested age difference.

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“…As the radius enters the tidal evolution at the 5 th power, the radial contraction is a major effect. Khaliullin and Khaliullina (2011) revisited this point and found that, although radial contraction does play a major role, they were unable to combine models of the equilibrium tide and radial contraction to match observations. Weinberg et al (2011) tested the linear theory against nonlinear models and found that in general the linear theory does not capture the physics of the more sophisticated approach.…”

Section: E4 Tidal Response In Celestial Bodiesmentioning

confidence: 99%

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

et al. 2013

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Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at highenough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets ''Tidal Venuses'' and the phenomenon a ''tidal greenhouse.'' Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses < 0.3 M Sun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a *4.5 M Earth planet orbiting a 0.3 M Sun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

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Orbital circularization of close binary stars on the pre-main sequence

Cited by 23 publications

References 90 publications

On the Lack of Circumbinary Planets Orbiting Isolated Binary Stars

On the Lack of Circumbinary Planets Orbiting Isolated Binary Stars

Luminosity Discrepancy in the Equal-Mass, Pre-Main-Sequence Eclipsing Binary Par 1802: Non-Coevality or Tidal Heating?

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

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