The Banana Project. V. Misaligned and Precessing Stellar Rotation Axes in Cv Velorum

Albrecht, S.; Winn, Joshua N.; Torres, Guillermo; Fabrycky, Daniel C.; Setiawan, J.; Gillon, M.; Jehin, Emmanuël; Triaud, A. H. M. J.; Queloz, D.; Snellen, I. A. G.; Eggleton, P. P.

doi:10.1088/0004-637x/785/2/83

Cited by 79 publications

(51 citation statements)

References 42 publications

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“…We anticipate that more detailed studies of (subsamples of) the Kepler EB sample will further constrain tidal circularization theory. We also expect our findings to be of interest in the context of tidal theory for stellar obliquities in double star systems (e.g., Albrecht et al 2014) and in exoplanet systems (e.g., Winn et al 2010;Albrecht et al 2012).…”

Section: Discussionmentioning

confidence: 78%

Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

Eylen

Winn

Albrecht

2016

ApJ

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The rate of tidal circularization is predicted to be faster for relatively cool stars with convective outer layers, compared to hotter stars with radiative outer layers. Observing this effect is challenging because it requires large and well-characterized samples that include both hot and cool stars. Here we seek evidence of the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler. This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure e cos ω based on the relative timing of the primary and secondary eclipses. We examine the distribution of e cos ω as a function of period for binaries composed of hot stars, cool stars, and mixtures of the two types. At the shortest periods, hot-hot binaries are most likely to be eccentric; for periods shorter than four days, significant eccentricities occur frequently for hot-hot binaries, but not for hot-cool or coolcool binaries. This is in qualitative agreement with theoretical expectations based on the slower dissipation rates of hot stars. However, the interpretation of our results is complicated by the largely unknown ages and evolutionary states of the stars in our sample.

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Section: Discussionmentioning

confidence: 78%

Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

Eylen

Winn

Albrecht

2016

ApJ

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“…Some binary stars possess rotation spins inclined with respect to their orbital spin (e.g. Albrecht et al 2009;Zhou & Huang 2013;Albrecht et al 2014) and may reflect the same processes that lead to inclined discs. Proto-binaries formed by fragmentation must have an initial separation larger than 10 AU, with typical separations larger than 100 AU (Bate 2012).…”

Section: Observational and Theoretical Evidence Of Mutually Inclined mentioning

confidence: 99%

Planets transiting non-eclipsing binaries

Martin

Triaud

2014

A&A

106

141

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The majority of binary stars do not eclipse. Current searches for transiting circumbinary planets concentrate on eclipsing binaries, and are therefore restricted to a small fraction of potential hosts. We investigate the concept of finding planets transiting non-eclipsing binaries, whose geometry would require mutually inclined planes. Using an N-body code we explore how the number and sequence of transits vary as functions of observing time and orbital parameters. The concept is then generalised thanks to a suite of simulated circumbinary systems. Binaries are constructed from radial-velocity surveys of the solar neighbourhood. They are then populated with orbiting gas giants, drawn from a range of distributions. The binary population is shown to be compatible with the Kepler eclipsing binary catalogue, indicating that the properties of binaries may be as universal as the initial mass function. These synthetic systems produce transiting circumbinary planets occurring on both eclipsing and non-eclipsing binaries. Simulated planets transiting eclipsing binaries are compared with published Kepler detections. We find 1) that planets transiting non-eclipsing binaries are probably present in the Kepler data; 2) that observational biases alone cannot account for the observed over-density of circumbinary planets near the stability limit, which implies a physical pile-up; and 3) that the distributions of gas giants orbiting single and binary stars are likely different. Estimating the frequency of circumbinary planets is degenerate with the spread in mutual inclination. Only a minimum occurrence rate can be produced, which we find to be compatible with 9%. Searching for inclined circumbinary planets may significantly increase the population of known objects and will test our conclusions. Their presence, or absence, will reveal the true occurrence rate and help develop circumbinary planet formation theories.

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“…We also aim to revisit the relative frequencies of low-mass stars to planets, to brown dwarfs in order to confirm the presence, extent and dryness of the brown dwarf desert (Marcy & Butler 2000;Grether & Lineweaver 2006;Sahlmann et al 2011;Ma & Ge 2014). We will compare the stellar and planetary eccentricity/period and eccentricity/mass distributions in order to study tides (Zahn & Bouchet 1989;Mathieu et al 1990;Mazeh et al 1997;Terquem et al 1998;Meibom & Mathieu 2005;Milliman et al 2014), investigate whether the statistics on the presence of additional perturbing bodies are similar (Tokovinin et al 2006;Knutson et al 2014;Neveu-VanMalle et al 2016), and find out if the spinorbit misalignments frequently observed in hot Jupiter systems are also observed in binary stars thanks to the RossiterMcLaughlin effect (Hale 1994;Triaud et al 2010;Albrecht et al 2014;Esposito et al 2014;Lendl et al 2014;Winn & Fabrycky 2015).…”

Section: Introductionmentioning

confidence: 99%

The EBLM Project

Triaud

Martin

Ségransan

et al. 2017

A&A

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125

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We present 2271 radial velocity measurements taken on 118 single-line binary stars, taken over eight years with the CORALIE spectrograph. The binaries consist of F/G/K primaries and M dwarf secondaries. They were initially discovered photometrically by the WASP planet survey, as their shallow eclipses mimic a hot Jupiter transit. The observations we present permit a precise characterisation of the binary orbital elements and mass function. With modelling of the primary star, this mass function is converted to a mass of the secondary star. In the future, this spectroscopic work will be combined with precise photometric eclipses to draw an empirical mass/radius relation for the bottom of the mass sequence. This has applications in both stellar astrophysics and the growing number of exoplanet surveys around M dwarfs. In particular, we have discovered 34 systems with a secondary mass below 0.2 M , and so we will ultimately double the number of known very low-mass stars with well-characterised masses and radii. The quality of our data combined with the amplitude of the Doppler variations mean that we are able to detect eccentricities as small as 0.001 and orbital periods to sub-second precision. Our sample can revisit some earlier work on the tidal evolution of close binaries, extending it to low mass ratios. We find some exceptional binary systems that are eccentric at orbital periods below three days, while our longest circular orbit has a period of 10.4 days. Amongst our systems, we note one remarkable architecture in J1146-42 that boasts three stars within one astronomical unit. By collating the EBLM binaries with published WASP planets and brown dwarfs, we derive a mass spectrum with twice the resolution of previous work. We compare the WASP/EBLM sample of tightly bound orbits with work in the literature on more distant companions up to 10 AU. We note that the brown dwarf desert appears wider, as it carves into the planetary domain for our short-period orbits. This would mean that a significantly reduced abundance of planets begins at ∼3 M Jup , well before the deuterium-burning limit. This may shed light on the formation and migration history of massive gas giants.

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The Banana Project. V. Misaligned and Precessing Stellar Rotation Axes in Cv Velorum

Cited by 79 publications

References 42 publications

Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

Planets transiting non-eclipsing binaries

The EBLM Project

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