Accretion Onto Planetary Mass Companions of Low-Mass Young Stars

Zhou, Yifan; Herczeg, Gregory J.; Kraus, Adam L.; Metchev, Stanimir; Cruz, Kelle L.

doi:10.1088/2041-8205/783/1/l17

Cited by 118 publications

(170 citation statements)

References 48 publications

(74 reference statements)

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“…For DH Tau b, we calculate a luminosity of 0.0021 L e using the radius and stellar temperature (Zhou et al 2014). van der Plas et al (2016) provide a scaling relation between stellar luminosity and disk temperature for low-mass…”

Section: Circumplanetary Disk Models and Resultsmentioning

confidence: 99%

“…All ofthese mechanisms require that a forming planet builds up from its own circumplanetary disk that formed either from the surrounding cloud, or from the massive disk around the host star. Indirect evidence for the presence of such disks is provided by the fact that planet-mass companions in young systems are powerful a H emitters, e.g., OTS 44, GSC 06214-00210 b, GQ Lupi b, FW Tau c, and DH Tau b (Joergens et al 2013;Zhou et al 2014). The a H emission, or some portion of it, being the trace of accretion from the disk onto the companion.…”

Section: Introductionmentioning

confidence: 99%

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An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*

Wolff

Ménard

Cáceres

et al. 2017

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DHTau is a young (∼1 Myr) classical TTauri star. It is one of the few young PMS stars known to be associated with a planetary mass companion, DHTaub, orbiting at large separation and detected by direct imaging. DHTaub is thought to be accreting based on copious a H emission and exhibits variable Paschen Beta emission. NOEMA observations at 230 GHz allow us to place constraints on the disk dust mass for both DHTaub and the primary in a regime where the disks will appear optically thin. We estimate a disk dust mass for the primary,, which gives a disktostar mass ratio of 0.014 (assuming the usual gas todust mass ratio of 100 in the disk). We find a conservative disk dust mass upper limit of 0.42 M ⊕ for DHTaub, assuming that the disk temperature is dominated by irradiation from DH Tau b itself. Given the environment of the circumplanetary disk, variable illumination from the primary or the equilibrium temperature of the surrounding cloud would lead to even lower disk mass estimates. AMCFOST radiative transfer model, including heating of the circumplanetary disk by DHTaub and DHTauA, suggests that a mass-averaged disk temperature of 22 K is more realistic, resulting in a dust disk mass upper limit of 0.09 M ⊕ for DHTaub. We place DHTaub in context with similar objects and discuss the consequences for planet formation models.

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Section: Circumplanetary Disk Models and Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*

Wolff

Ménard

Cáceres

et al. 2017

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“…While the total accretional luminosity should remain similar in such more complex geometries for a fixed planetary mass, radius, and gas accretion rate, the characteristic surface over which it is radiated may change, meaning that the SED would be different than when assuming that the accretional luminosity originates homogeneously from the planet's entire surface. This could have important observational consequences (e.g., Zhou et al 2014;Eisner 2015;Zhu 2015;Szulágyi & Mordasini 2017) and must therefore be critically kept in mind.…”

Section: Thermodynamics Of the Accretion Processmentioning

confidence: 99%

Characterization of exoplanets from their formation

Mordasini

Marleau

Mollière

2017

A&A

111

142

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Context. This paper continues a series in which we predict the main observable characteristics of exoplanets based on their formation. In Paper I we described our global planet formation and evolution model that is based on the core accretion paradigm. In Paper II we studied the planetary mass-radius relationship with population syntheses. Aims. In this paper we present an extensive study of the statistics of planetary luminosities during both formation and evolution. Our results can be compared with individual directly imaged extrasolar (proto)planets and with statistical results from surveys. Methods. We calculated three populations of synthetic planets assuming different efficiencies of the accretional heating by gas and planetesimals during formation. We describe the temporal evolution of the planetary mass-luminosity relation. We investigate the relative importance of the shock and internal luminosity during formation, and predict a statistical version of the post-formation mass vs. entropy "tuning fork" diagram. Because the calculations now include deuterium burning we also update the planetary mass-radius relationship in time.Results. We find significant overlap between the high post-formation luminosities of planets forming with hot and cold gas accretion because of the core-mass effect. Variations in the individual formation histories of planets can still lead to a factor 5 to 20 spread in the post-formation luminosity at a given mass. However, if the gas accretional heating and planetesimal accretion rate during the runaway phase is unknown, the post-formation luminosity may exhibit a spread of as much as 2-3 orders of magnitude at a fixed mass. As a key result we predict a flat log-luminosity distribution for giant planets, and a steep increase towards lower luminosities due to the higher occurrence rate of low-mass (M 10-40 M ⊕ ) planets. Future surveys may detect this upturn. Conclusions. Our results indicate that during formation an estimation of the planetary mass may be possible for cold gas accretion if the planetary gas accretion rate can be estimated. If it is unknown whether the planet still accretes gas, the spread in total luminosity (internal+accretional) at a given mass may be as large as two orders of magnitude, therefore inhibiting the mass estimation. Due to the core-mass effect even planets which underwent cold accretion can have large post-formation entropies and luminosities, such that alternative formation scenarios such as gravitational instabilities do not need to be invoked. Once the number of self-luminous exoplanets with known ages and luminosities increases, the resulting luminosity distributions may be compared with our predictions.

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“…1). On the observational side, some planetary-mass companions identified by direct imaging in young clusters show evidence for active accretion and are surrounded by massive disks (see, e.g., Seifahrt et al 2007;Bowler et al 2011;Joergens et al 2013;Zhou et al 2014). This also argues for an extension of the stellar/BD formation mechanisms in the planetary-mass regime.…”

Section: Discussionmentioning

confidence: 99%

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits

Reggiani

Meyer

Chauvin

et al. 2016

A&A

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Context. In recent years there have been many attempts to characterize the occurrence and distribution of stellar, brown dwarf (BD), and planetary-mass companions to solar-type stars with the aim of constraining formation mechanisms. From radial velocity observations a dearth of companions with masses between 10-40 M Jupiter has been noticed at close separations, suggesting the possibility of a distinct formation mechanism for objects above and below this range. Aims. We present a model for the substellar companion mass function (CMF). This model consists of the superposition of the planet and BD companion mass distributions, assuming that we can extrapolate the radial velocity measured CMF for planets to larger separations and the stellar companion mass-ratio distribution over all separations into the BD mass regime. By using both the results of the VLT/NaCo large program (NaCo-LP) and the complementary archive datasets, which probe the occurrence of planets and BDs on wide orbits around solar-type stars, we place some constraints on the planet and BD distributions. Methods. We developed a Monte Carlo simulation tool to predict the outcome of a given survey, depending on the shape of the orbital parameter distributions (mass, semimajor axis, eccentricity, and inclination). Comparing the predictions with the results of the observations, we calculate the likelihood of different models and which models can be ruled out. Results. Current observations are consistent with the proposed model for the CMF, as long as a sufficiently small outer truncation radius ( 100 AU) is introduced for the planet separation distribution. Some regions of parameter space can be excluded by the observations. Conclusions. We conclude that the results of the direct imaging surveys searching for substellar companions around Sun-like stars are consistent with a combined substellar mass spectrum of planets and BDs. This mass distribution has a minimum between 10 and 50 M Jupiter , in agreement with radial velocity measurements. In this picture the dearth of objects in this mass range would naturally arise from the shape of the mass distribution, without the introduction of any distinct formation mechanism for BDs. This kind of model for the CMF allows us to determine the probability for a substellar companion as a function of mass to have formed in a disk or from protostellar core fragmentation, as such mechanisms overlap in this mass range.

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Accretion Onto Planetary Mass Companions of Low-Mass Young Stars

Cited by 118 publications

References 48 publications

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*

Characterization of exoplanets from their formation

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits

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Accretion Onto Planetary Mass Companions of Low-Mass Young Stars

Cited by 118 publications

References 48 publications

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b*

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b*

Characterization of exoplanets from their formation

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits

Contact Info

Product

Resources

About

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*

An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b^*