Publications by Caroline Terquem

First-order mean motion resonances in two-planet systems: general analysis and observed systems


C Terquem, JCB Papaloizou

The TRAPPIST-1 system: orbital evolution, tidal dissipation, formation and habitability


JCB Papaloizou, E Szuszkiewicz, C Terquem

On the energy dissipation rate at the inner edge of circumbinary discs


C Terquem, JCB Papaloizou

On the formation of planetary systems in photoevaporating transition discs


C Terquem

CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk


E Gillen, S Aigrain, C Terquem, J Bouvier, SHP Alencar, D Gandolfi, J Stauffer, A Cody, L Venuti, P Viana Almeida, G Micela, F Favata, HJ Deeg

A circumbinary disc model for the variability of the eclipsing binary CoRoT 223992193


C Terquem, PM Sorensen-Clark, J Bouvier

CoRoT 223992193: A new, low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk

Astronomy and Astrophysics EDP Sciences 562 (2014) 50-69

E Gillen, S Aigrain, A McQuillan, J Bouvier, S Hodgkin, SHP Alencar, C Terquem, J Southworth, NP Gibson, AM Cody, M Lendl, M Morales-Calderón, F Favata, J Stauffer, G Micela

We present the discovery of CoRoT 223992193, a double-lined, detached eclipsing binary, comprising two pre-main sequence M dwarfs, discovered by the CoRoT space mission during a 23-day observation of the 3 Myr old NGC 2264 star-forming region. Using multi-epoch optical and near-IR follow-up spectroscopy with FLAMES on the Very Large Telescope and ISIS on the William Herschel Telescope we obtain a full orbital solution and derive the fundamental parameters of both stars by modelling the light curve and radial velocity data. The orbit is circular and has a period of $3.8745745 \pm 0.0000014$ days. The masses and radii of the two stars are $0.67 \pm 0.01$ and $0.495 \pm 0.007$ $M_{\odot}$ and $1.30 \pm 0.04$ and $1.11 ~^{+0.04}_{-0.05}$ $R_{\odot}$, respectively. This system is a useful test of evolutionary models of young low-mass stars, as it lies in a region of parameter space where observational constraints are scarce; comparison with these models indicates an apparent age of $\sim$3.5-6 Myr. The systemic velocity is within $1\sigma$ of the cluster value which, along with the presence of lithium absorption, strongly indicates cluster membership. The CoRoT light curve also contains large-amplitude, rapidly evolving out-of-eclipse variations, which are difficult to explain using starspots alone. The system's spectral energy distribution reveals a mid-infrared excess, which we model as thermal emission from a small amount of dust located in the inner cavity of a circumbinary disk. In turn, this opens up the possibility that some of the out-of-eclipse variability could be due to occultations of the central stars by material located at the inner edge or in the central cavity of the circumbinary disk.

On the formation of the Kepler-10 planetary system


C Terquem

Evolution of eccentricity and orbital inclination of migrating planets in 2:1 mean motion resonance


J Teyssandier, C Terquem

The effects of disc warping on the inclination of planetary orbits

MNRAS (2013)

C Terquem

Orbital evolution of a planet on an inclined orbit interacting with a disc

Monthly Notices of the Royal Astronomical Society 428 (2013) 658-669

J Teyssandier, C Terquem, JCB Papaloizou

Protoplanets with core masses below the critical mass fill in their Roche lobe

Monthly Notices of the Royal Astronomical Society 418 (2011) 1928-1934

C Terquem, T Heinemann

We study the evolution of a protoplanet of a few earth masses embedded in a protoplanetary disc. If we assume that the atmosphere of the protoplanet, i.e. the volume of gas in hydrostatic equilibrium bound to the core, has a surface radius smaller than the Roche lobe radius, we show that it expands as it accretes both planetesimals and gas at a fixed rate from the nebula until it fills in the Roche lobe. The evolution occurs on a time-scale shorter than the formation or migration time-scales. Therefore, we conclude that protoplanets of a few earth masses have an atmosphere that extends to the Roche lobe surface, where it joins on to the nebula. This is true even when the Bondi radius is smaller than the Roche lobe radius. This is in contrast to the commonly used models in which the static atmosphere extends up to the Bondi radius and is surrounded by a cold accretion flow. As a result, any calculation of the tidal torque exerted by the disc on to the protoplanet should exclude the material present in the Roche lobe, since it is bound to the protoplanet. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Disk dynamics and planet migration

EAS Publications Series 41 (2010) 209-218

CEJMLJ Terquem

We review models of protoplanetary disks. In the earlier stages of evolution, disks are subject to gravitational instabilities that redistribute mass and angular momentum on short timescales. Later on, when the mass of the disk is below ten percent or so of that of the central star, accretion occurs through the magnetorotational instability. The parts of the disks that are not ionized enough to couple to the magnetic field may not accrete or accrete inefficiently. We also review theories of planet migration. Tidal interaction between a disk and an embedded planet leads to angular momentum exchange between the planetary orbital motion and the disk rotation. This results in low mass planets migrating with respect to the gas in the disk, while massive planets open up a gap in the vicinity of their orbit and migrate in as the disk is accreted. © EAS, EDP Sciences, 2010.

On the dynamics of multiple systems of hot super-Earths and Neptunes: Tidal circularization, resonance and the HD 40307 system

Monthly Notices of the Royal Astronomical Society 405 (2010) 573-592

JCB Papaloizou, C Terquem

In this paper, we consider the dynamics of a system of hot super-Earths or Neptunes such as HD 40307. We show that, as tidal interaction with the central star leads to small eccentricities, the planets in this system could be undergoing resonant coupling even though the period ratios depart significantly from very precise commensurability. In a three-planet system, this is indicated by the fact that resonant angles librate or are associated with long-term changes to the orbital elements. In HD 40307, we expect that three resonant angles could be involved in this way. We propose that the planets in this system were in a strict Laplace resonance while they migrated through the disc. After entering the disc inner cavity, tidal interaction would cause the period ratios to increase from two but with the inner pair deviating less than the outer pair, counter to what occurs in HD 40307. However, the relationship between these pairs that occur in HD 40307 might be produced if the resonance is impulsively modified by an event like a close encounter shortly after the planetary system decouples from the disc. We find this to be in principle possible for a small relative perturbation on the order of a few ×10-3, but then we find that the evolution to the present system in a reasonable time is possible only if the masses are significantly larger than the minimum masses and the tidal dissipation is very effective. On the other hand, we found that a system like HD 40307 with minimum masses and more realistic tidal dissipation could be produced if the eccentricity of the outermost planet was impulsively increased to ∼0.15. We remark that the form of resonantly coupled tidal evolution we consider here is quite general and could be of greater significance for systems with inner planets on significantly shorter orbital periods characteristic of, for example, CoRoT 7 b. © 2010 The Authors. Journal compilation © 2010 RAS.

Eccentricity pumping of a planet on an inclined orbit by a disc

Monthly Notices of the Royal Astronomical Society 404 (2010) 409-414

C Terquem, A Ajmia

In this paper, we show that the eccentricity of a planet on an inclined orbit with respect to a disc can be pumped up to high values by the gravitational potential of the disc, even when the orbit of the planet crosses the disc plane. This process is an extension of the Kozai effect. If the orbit of the planet is well inside the disc inner cavity, the process is formally identical to the classical Kozai effect. If the planet's orbit crosses the disc but most of the disc mass is beyond the orbit, the eccentricity of the planet grows when the initial angle between the orbit and the disc is larger than some critical value which may be significantly smaller than the classical value of 39{ring operator}. Both the eccentricity and the inclination angle then vary periodically with time. When the period of the oscillations of the eccentricity is smaller than the disc lifetime, the planet may be left on an eccentric orbit as the disc dissipates. © 2010 The Authors. Journal compilation. © 2010 RAS.

New composite models of partially ionized protoplanetary disks

Astrophysical Journal 689 (2008) 532-538

CEJML Terquem

Migration and the formation of systems of hot super-earths and neptunes

Astrophysical Journal 654 (2007) 1110-1120

C Terquem, JCB Papaloizou

Planet formation and migration

Reports on Progress in Physics 69 (2006) 119-180

JCB Papaloizou, C Terquem

We review the observations of extrasolar planets, ongoing developments in theories of planet formation, orbital migration and the evolution of multiplanet systems. © 2006 IOP Publishing Ltd.

Numerical simulations of type i planetary migration in non-turbulent magnetized discs

Monthly Notices of the Royal Astronomical Society 363 (2005) 943-953

S Fromang, C Terquem, RP Nelson

Using 2D magnetohydrodynamic (MHD) numerical simulations performed with two different finite-difference Eulerian codes, we analyse the effect that a toroidal magnetic field has on low-mass planet migration in non-turbulent protoplanetary discs. The presence of the magnetic field modifies the waves that can propagate in the disc. In agreement with a recent linear analysis, we find that two magnetic resonances develop on both sides of the planet orbit, which contribute to a significant global torque. In order to measure the torque exerted by the disc on the planet, we perform simulations in which the latter is either fixed on a circular orbit or allowed to migrate. For a 5-M⊕ planet, when the ratio β between the square of the sound speed and that of the Alfven speed at the location of the planet is equal to 2, we find inward migration when the magnetic field Bφ is uniform in the disc, reduced migration when Bφ decreases as r -1 and outward migration when Bφ decreases as r -2. These results are in agreement with predictions from the linear analysis. Taken as a whole, our results confirm that even a subthermal stable field can stop inward migration of an earth-like planet. © 2005 RAS.

Evolution of self-gravitating magnetized disks. II. Interaction between magnetohydrodynamic turbulence and gravitational instabilities

ASTROPHYSICAL JOURNAL 616 (2004) 364-375

S Fromang, SA Balbus, C Terquem, JP De Villiers