Friends of Hot Jupiters. Iii. An Infrared Spectroscopic Search for Low-Mass Stellar Companions

Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy

doi:10.1088/0004-637x/814/2/148

Cited by 62 publications

(41 citation statements)

References 126 publications

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“…In extending the N00 conclusion, we are mindful of apparently contradictory data embodied in the detections of planets in mature binary systems (see e.g., Desidera & Barbieri 2007;Ngo et al 2015;Piskorz et al 2015). In many cases, these systems are characterized by semimajor axes similar to that found in GG Tau A, making the contradiction more acute.…”

Section: The Likelihood For Planet Formationmentioning

confidence: 87%

DYNAMICS OF CIRCUMSTELLAR DISKS III: THE CASE OF GG Tau A

Nelson

Marzari

2016

ApJ

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We present two-dimensional hydrodynamic simulations using the Smoothed Particle Hydrodynamic code, VINE, to model a self-gravitating binary system. We model configurations in which a circumbinary torus+disk surrounds a pair of stars in orbit around each other and a circumstellar disk surrounds each star, similar to that observed for the GG Tau A system. We assume that the disks cool as blackbodies, using rates determined independently at each location in the disk by the time dependent temperature of the photosphere there. We assume heating due to hydrodynamical processes and to radiation from the two stars, using rates approximated from a measure of the radiation intercepted by the disk at its photosphere. We simulate a suite of systems configured with semimajor axes of either a = 62 AU ("wide") or a = 32 AU ("close"), and with assumed orbital eccentricity of either e = 0 or e = 0.3. Each simulation follows the evolution for ∼6500-7500 yr, corresponding to about three orbits of the torus around the center of mass. Our simulations show that strong, sharply defined spiral structures are generated from the stirring action of the binary and that, in some cases, these structures fragment into 1-2 massive clumps. The torus quickly fragments into several dozen such fragments in configurations in which either the binary is replaced by a single star of equal mass, or radiative heating is neglected. The spiral structures extend inwards to the circumstellar environment as large scale material streams for which most material is found on trajectories that return it to the torus on a timescale of 1-200 yr, with only a small fraction accreting into the circumstellar environment. The spiral structures also propagate outwards through the torus, generating net outwards mass flow, and eventually losing coherence at large distances from the stars. The torus becomes significantly eccentric in shape over most of its evolution. In all configurations, accretion onto the stars occurs at a steady rate of a few ×10 −8 M e yr −1 , with the net result that, without replenishment, the disk lifetimes would be shorter than ∼10 4 yr. Our simulations show that only wide orbit configurations are able to retain circumstellar disks, by virtue of accretion driven from the robust material streams generated in wide configurations, which are very weak in close configurations. In wide, eccentric orbit configurations, accretion is episodic and occurs preferentially onto the secondary, with rates strongly peaked near the binary periapse. Based on our results, we conclude that the GG Tau A torus is strongly self gravitating and that a major contribution to its thermal energy input is the shock dissipation associated with spiral structures generated both by self gravitating disturbances and by the stirring action of the binary. We interpret the sharply defined features observed in the torus as manifestations of such spiral structures. We interpret the low density disk surrounding it as an excretion disk created by the outward mass flux generated by ...

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Section: The Likelihood For Planet Formationmentioning

confidence: 87%

DYNAMICS OF CIRCUMSTELLAR DISKS III: THE CASE OF GG Tau A

Nelson

Marzari

2016

ApJ

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“…In fact, Knutson et al (2014) detected a trend in the RV data and interpreted it as an additional companion of either planetary or stellar size. The K-band high-resolution spectroscopy of HAT-P-32 of Piskorz et al (2015) ruled out an object hotter than 3500 K. Thus, the object causing the RV trend cannot be luminous enough to be responsible for the observed slope in the transmission spectrum. An AO search by Ngo et al (2015) did not detect an additional unknown stellar object either gravitationally bound or by chance aligned along the line of sight.…”

Section: Additional Third-light Contributionmentioning

confidence: 99%

Transmission spectroscopy of HAT-P-32b with the LBT: confirmation of clouds/hazes in the planetary atmosphere

Mallonn

Strassmeier

2016

A&A

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Aims. Spectroscopic observations of a transit event of an extrasolar planet offer the opportunity to study the composition of the planetary atmosphere. This can be done with comparably little telescope time using a low-resolution multi-object spectrograph at a large aperture telescope. We observed a transit of the inflated hot Jupiter HAT-P-32b with the Multi-Object Double Spectrograph at the Large Binocular Telescope to characterize its atmosphere from 3300 to 10 000 Å. Methods. A time series of target and reference star spectra was binned in two broad-band wavelength channels, from which differential transit light curves were constructed. These broad-band light curves were used to confirm previous transit parameter determinations. To derive the planetary transmission spectrum with a resolution of R ∼ 60, we created a chromatic set of 62 narrow-band light curves. The spectrum was corrected for the third light of a nearby M star. Additionally, we undertook a photometric monitoring campaign of the host star to correct for the influence of starspots. Results. The transmission spectrum of HAT-P-32b shows no pressure-broadened absorption features from Na and K, which is interpreted by the presence of clouds or hazes in the planetary atmosphere. This result is in agreement with previous studies on the same planet. The presence of TiO in gas phase could be ruled out. We find a 2.8σ indication of increased absorption in the line core of potassium (K I 7699 Å). No narrow absorption features of Na and Hα were detected. Furthermore, tentative indications were found for a slope of increasing opacity toward blue wavelengths from the near-IR to the near-UV with an amplitude of two scale heights. If confirmed by follow-up observations, it can be explained by aerosols either causing Mie scattering or causing Rayleigh scattering with an aerosol -gas scale height ratio below unity. The host star was found to be photometrically stable within the measurement precision.

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“…Previous studies have investigated these theories in several contexts, including but not limited to spin-orbit misalignment (Naoz et al 2012;Rogers et al 2012), stellar metallicity (Dawson & Murray-Clay 2013), and the presence of additional companions (Knutson et al 2014;Ngo et al 2015;Piskorz et al 2015;Bryan et al 2016;Ngo et al 2016;Schlaufman & Winn 2016). The focus of this paper will be in the context of the Roche separation a Roche between the planet and host star.…”

Section: Introductionmentioning

confidence: 99%

Evidence for Two Hot-Jupiter Formation Paths

Nelson¹,

Rasio²

2017

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Disk migration and high-eccentricity migration are two well-studied theories to explain the formation of hot Jupiters. The former predicts that these planets can migrate up until the planet-star Roche separation (a Roche ) and the latter predicts they will tidally circularize at a minimum distance of 2a Roche . Considering long-running radial velocity and transit surveys have identified a couple hundred hot Jupiters to date, we can revisit the classic question of hot Jupiter formation in a data-driven manner. We approach this problem using data from several exoplanet surveys (radial velocity, Kepler, HAT, and WASP) allowing for either a single population or a mixture of populations associated with these formation channels, and applying a hierarchical Bayesian mixture model of truncated power laws of the form x γ−1 to constrain the population-level parameters of interest (e.g., location of inner edges, γ, mixture fractions). Within the limitations of our chosen models, we find the current radial velocity and Kepler sample of hot Jupiters can be well explained with a single truncated power law distribution with a lower cutoff near 2a Roche , a result that still holds after a decade, and γ = −0.51± 0.19 0.20 . However, the HAT and WASP data show evidence for multiple populations (Bayes factor ≈ 10 21 ). We find that 15 ± 9 6 % reside in a component consistent with disk migration (γ = −0.04± 0.53 1.27 ) and 85 ± 6 9 % in one consistent with high-eccentricity migration (γ = −1.38± 0.32 0.47 ). We find no immediately strong connections with some observed host star properties and speculate on how future exoplanet surveys could improve upon hot Jupiter population inference.

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Friends of Hot Jupiters. Iii. An Infrared Spectroscopic Search for Low-Mass Stellar Companions

Cited by 62 publications

References 126 publications

DYNAMICS OF CIRCUMSTELLAR DISKS III: THE CASE OF GG Tau A

DYNAMICS OF CIRCUMSTELLAR DISKS III: THE CASE OF GG Tau A

Transmission spectroscopy of HAT-P-32b with the LBT: confirmation of clouds/hazes in the planetary atmosphere

Evidence for Two Hot-Jupiter Formation Paths

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