Physical and orbital properties of<i>β</i>Pictoris b

Bonnefoy, M.; Marleau, Gabriel-Dominique; Galicher, R.; Beust, H.; Lagrange, Anne-Marie; Baudino, J. L.; Chauvin, G.; Borgniet, S.; Meunier, N.; Rameau, Julien; Boccaletti, A.; Cumming, Andrew; Helling, Christiane; Homeier, D.; Allard, F.; Delorme, P.

doi:10.1051/0004-6361/201424041

Cited by 72 publications

(102 citation statements)

References 43 publications

(71 reference statements)

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“…For instance, the presently available spectra of the exoplanet β Pictoris b are known to be reproduced by those of young L0-L1 dwarfs (Bonnefoy et al 2014b;Chilcote et al 2015). The same happens for AB Pic b (Bonnefoy et al 2010) or 1RXS J160929.1-210524 b (Manjavacas et al 2014).…”

Section: Are the Hr8799 Planets Properties So Peculiar?mentioning

confidence: 86%

First light of the VLT planet finder SPHERE

Bonnefoy¹,

Zurlo²,

Baudino³

et al. 2016

A&A

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Context. The system of four planets discovered around the intermediate-mass star HR8799 offers a unique opportunity to test planet formation theories at large orbital radii and to probe the physics and chemistry at play in the atmospheres of self-luminous young (∼30 Myr) planets. We recently obtained new photometry of the four planets and low-resolution (R ∼ 30) spectra of HR8799 d and e with the SPHERE instrument (Paper III). Aims. In this paper (Paper IV), we aim to use these spectra and available photometry to determine how they compare to known objects, what the planet physical properties are, and how their atmospheres work. Methods. We compare the available spectra, photometry, and spectral energy distribution (SED) of the planets to field dwarfs and young companions. In addition, we use the extinction from corundum, silicate (enstatite and forsterite), or iron grains likely to form in the atmosphere of the planets to try to better understand empirically the peculiarity of their spectrophotometric properties. To conclude, we use three sets of atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) to determine which ingredients are critically needed in the models to represent the SED of the objects, and to constrain their atmospheric parameters (T eff , log g, M/H). Results. We find that HR8799d and e properties are well reproduced by those of L6-L8 dusty dwarfs discovered in the field, among which some are candidate members of young nearby associations. No known object reproduces well the properties of planets b and c. Nevertheless, we find that the spectra and WISE photometry of peculiar and/or young early-T dwarfs reddened by submicron grains made of corundum, iron, enstatite, or forsterite successfully reproduce the SED of these planets. Our analysis confirms that only the Exo-REM models with thick clouds fit (within 2σ) the whole set of spectrophotometric datapoints available for HR8799 d and e for T eff = 1200 K, log g in the range 3.0−4.5, and M/H = +0.5. The models still fail to reproduce the SED of HR8799c and b. The determination of the metallicity, log g, and cloud thickness are degenerate. Conclusions. Our empirical analysis and atmospheric modelling show that an enhanced content in dust and decreased CIA of H 2 is certainly responsible for the deviation of the properties of the planet with respect to field dwarfs. The analysis suggests in addition that HR8799c and b have later spectral types than the two other planets, and therefore could both have lower masses.

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Section: Are the Hr8799 Planets Properties So Peculiar?mentioning

confidence: 86%

First light of the VLT planet finder SPHERE

Bonnefoy¹,

Zurlo²,

Baudino³

et al. 2016

A&A

Self Cite

129

104

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“…For each molecule and each interval, we calculated a set of 10 −27 at 1500 K Yurchenko & Tennyson (2014) NH 3 5 × 10 −27 at 4000 K Yurchenko et al (2011) TiO, VO 10 −22 at 4000 K Plez (1998) Borysow (2002) Gaussian-Legendre quadrature for each of the two g l intervals.…”

Section: Spectroscopic Datamentioning

confidence: 99%

“…These are based on publications by Borysow et al (2001) and Borysow (2002) for H 2 -H 2 , and Borysow et al (1988 and for H 2 -He.…”

Section: Spectroscopic Datamentioning

confidence: 99%

“…All these models were used to constrain the main parameters, such as the effective temperature, surface gravity, atmospheric compounds, or radius of the detected planets (Neuhäuser et al 2005;Marley et al 2012;Bonnefoy et al 2013Bonnefoy et al , 2014Galicher et al 2014) and to predict abilities of new instruments (Boccaletti et al 2005;Hanot et al 2010;Vigan et al 2010). Most of these models are developed for BD and applied to exoplanets.…”

Section: Introductionmentioning

confidence: 99%

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Interpreting the photometry and spectroscopy of directly imaged planets: a new atmospheric model applied toβPictoris b and SPHERE observations

Baudino

Bézard

Boccaletti

et al. 2015

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Context. Since the end of 2013 a new generation of instruments optimized to image young giant planets around nearby stars directly is becoming available on 8-m class telescopes, both at Very Large Telescope and Gemini in the southern hemisphere. Beyond the achievement of high contrast and the discovery capability, these instruments are designed to obtain photometric and spectral information to characterize the atmospheres of these planets. Aims. We aim to interpret future photometric and spectral measurements from these instruments, in terms of physical parameters of the planets, with an atmospheric model using a minimal number of assumptions and parameters. Methods. We developed the Exoplanet Radiative-convective Equilibrium Model (Exo-REM) to analyze the photometric and spectroscopic data of directly imaged planets. The input parameters are a planet's surface gravity (g), effective temperature (T eff ), and elemental composition. The model predicts the equilibrium temperature profile and mixing ratio profiles of the most important gases. Opacity sources include the H 2 -He collision-induced absorption and molecular lines from eight compounds (including CH 4 updated with the Exomol line list). Absorption by iron and silicate cloud particles is added above the expected condensation levels with a fixed scale height and a given optical depth at some reference wavelength. Scattering was not included at this stage.Results. We applied Exo-REM to photometric and spectral observations of the planet β Pictoris b obtained in a series of near-infrared filters. We derived T eff = 1550 ± 150 K, log(g) = 3.5 ± 1, and radius R = 1.76 ± 0.24 R Jup (2σ error bars from photometric measurements). These values are comparable to those found in the literature, although with more conservative error bars, consistent with the model accuracy. We were able to reproduce, within error bars, the J-and H-band spectra of β Pictoris b. We finally investigated the precision to which the above parameters can be constrained from SPHERE measurements using different sets of near-infrared filters as well as low-resolution spectroscopy.

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“…These estimates do not depend on evolutionary models of giant planets (e.g., Burrows et al 1997;Chabrier et al 2000;Baraffe et al 2003;Marley et al 2007), which rely on unknown initial conditions (Marley et al 2007;Spiegel & Burrows 2012;Marleau & Cumming 2014), and on poorly constrained stellar ages. Thus, the derivation of the dynamical mass of young low-mass companions may help to calibrate the evolutionary models (e.g., Close et al 2005;Boden et al 2005;Crepp et al 2012;Bonnefoy et al 2014b).…”

Section: Introductionmentioning

confidence: 99%

The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system

Maire

Skemer

Hinz

et al. 2015

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Context. Astrometric monitoring of directly imaged exoplanets allows the study of their orbital parameters and system architectures. Because most directly imaged planets have long orbital periods (>20 AU), accurate astrometry is challenging when based on data acquired on timescales of a few years and usually with different instruments. The LMIRCam camera on the Large Binocular Telescope is being used for the LBT Exozodi Exoplanet Common Hunt (LEECH) survey to search for and characterize young and adolescent exoplanets in L band (3.8 µm), including their system architectures. Aims. We first aim to provide a good astrometric calibration of LMIRCam. Then, we derive new astrometry, test the predictions of the orbital model of 8:4:2:1 mean motion resonance proposed for the system, and perform new orbital fitting of the HR 8799 bcde planets. We also present deep limits on a putative fifth planet inside the known planets. Methods. We use observations of HR 8799 and the Θ 1 Ori C field obtained during the same run in October 2013. Results. We first characterize the distortion of LMIRCam. We determine a platescale and a true north orientation for the images of 10.707 ± 0.012 mas/pix and −0.430 ± 0.076 • , respectively. The errors on the platescale and true north orientation translate into astrometric accuracies at a separation of 1 of 1.1 mas and 1.3 mas, respectively. The measurements for all planets agree within 3σ with a predicted ephemeris. The orbital fitting based on the new astrometric measurements favors an architecture for the planetary system based on 8:4:2:1 mean motion resonance. The detection limits allow us to exclude a fifth planet slightly brighter or more massive than HR 8799 b at the location of the 2:1 resonance with HR 8799 e (∼9.5 AU) and about twice as bright as HR 8799 cde at the location of the 3:1 resonance with HR 8799 e (∼7.5 AU).

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Physical and orbital properties ofβPictoris b

Cited by 72 publications

References 43 publications

First light of the VLT planet finder SPHERE

First light of the VLT planet finder SPHERE

Interpreting the photometry and spectroscopy of directly imaged planets: a new atmospheric model applied toβPictoris b and SPHERE observations

The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system

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