GEMINI PLANET IMAGER SPECTROSCOPY OF THE HR 8799 PLANETS c AND d

Ingraham, Patrick; Marley, Mark S.; Saumon, D.; Marois, Christian; Macintosh, Bruce; Barman, Travis; Bauman, Brian; Burrows, Adam; Chilcote, Jeffrey; Rosa, Robert J. De; Dillon, Daren; Doyon, René; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald T.; Goodsell, Stephen J.; Graham, James R.; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Konopacky, Quinn; Larkin, J.; Maire, Jérôme; Marchis, Franck; McBride, James; Millar-Blanchaer, Max; Morzinski, Katie M.; Norton, Andrew; Oppenheimer, Ben R.; Palmer, Dave; Patience, Jennifer; Perrin, Marshall D.; Poyneer, Lisa; Pueyo, Laurent; Rantakyrö, Fredrik T.; Sadakuni, Naru; Saddlemyer, Leslie; Savransky, Dmitry; Soummer, Rémi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wiktorowicz, Sloane; Wolff, Schuyler

doi:10.1088/2041-8205/794/1/l15

Cited by 87 publications

(69 citation statements)

References 34 publications

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“…Previous studies of the HR8799 planets have also proposed that the photometric and spectroscopic properties of the objects could be explained by 1/ disequilibrium chemistry (Barman et al 2011a;Marley et al 2012;Skemer et al 2012Skemer et al , 2014Ingraham et al 2014), and/or 2/ patchy atmospheres (Marley et al 2012;Skemer et al 2012Skemer et al , 2014, and/or 3/ non-solar compositions (Barman et al 2011a;Konopacky et al 2013;Lee et al 2013;Barman et al 2015). The good fit in the 3−5 µm region for the planets d and e (along with the other wavelengths), despite the lack of non-equilibrium chemistry, non-solar metallicity compositions, and local variation of the cloud thickness in the models, suggest that these ingredients are not critically needed here.…”

Section: Are the Hr8799 Planets Properties So Peculiar?mentioning

confidence: 99%

“…The new generation of high-contrast imaging instruments such as SPHERE, GPI, and ScEXAO (Beuzit et al 2008;Macintosh et al 2014;Martinache & Guyon 2009) can now provide in a single shot the emission spectra of planets in the near-infrared (1−2.5 µm) at small angular separation without being limited by the contaminating stellar halo. Ingraham et al (2014) already presented K-band (1.9−2.4 µm) GPI low-resolution (R ∼ 60 to 80) spectra for planets c and d. In this paper we take advantage of the new low-resolution (R ∼ 30) 0.98−1.64 µm spectra of HR8799d and e, and photometry of the four planets, obtained by SPHERE (Zurlo et al 2016, hereafter Paper III), and of previously published photometry of the planets, to reinvestigate the properties of the planets.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

First light of the VLT planet finder SPHERE

Bonnefoy¹,

Zurlo²,

Baudino³

et al. 2016

A&A

130

104

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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: 99%

Section: Introductionmentioning

confidence: 99%

First light of the VLT planet finder SPHERE

Bonnefoy¹,

Zurlo²,

Baudino³

et al. 2016

A&A

130

104

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“…Figures 9 and 10 show that the J, H2, and H3 photometry of HR 8799 d and e is consistent with the spectra extracted from the IFS datacubes. We also included the flux-calibrated K-band GPI spectrum of HR 8799 d obtained by Ingraham et al (2014). This spectrum is compatible with IRDIS K1 and K2 photometry of the planet.…”

Section: Near-infrared Slopementioning

confidence: 99%

First light of the VLT planet finder SPHERE

Zurlo

Vigan

Galicher

et al. 2016

A&A

144

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Context. The planetary system discovered around the young A-type HR 8799 provides a unique laboratory to: a) test planet formation theories; b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology. Aims. We present and exploit new near-infrared images and integral-field spectra of the four gas giants surrounding HR 8799 obtained with SPHERE, the new planet finder instrument at the Very Large Telescope, during the commissioning and science verification phase of the instrument (July-December 2014). With these new data, we contribute to completing the spectral energy distribution (SED) of these bodies in the 1.0-2.5 µm range. We also provide new astrometric data, in particular for planet e, to further constrain the orbits. Methods. We used the infrared dual-band imager and spectrograph (IRDIS) subsystem to obtain pupil-stabilized, dual-band H2H3 (1.593 µm, 1.667 µm), K1K2 (2.110 µm, 2.251 µm), and broadband J (1.245 µm) images of the four planets. IRDIS was operated in parallel with the integral field spectrograph (IFS) of SPHERE to collect low-resolution (R ∼ 30), near-infrared (0.94-1.64 µm) spectra of the two innermost planets HR 8799 d and e. The data were reduced with dedicated algorithms, such as the Karhunen-Loève image projection (KLIP), to reveal the planets. We used the so-called negative planets injection technique to extract their photometry, spectra, and measure their positions. We illustrate the astrometric performance of SPHERE through sample orbital fits compatible with SPHERE and literature data. Results. We demonstrated the ability of SPHERE to detect and characterize planets in this kind of systems, providing spectra and photometry of its components. The spectra improve upon the signal-to-noise ratio of previously obtained data and increase the spectral coverage down to the Y band. In addition, we provide the first detection of planet e in the J band. Astrometric positions for planets HR 8799 bcde are reported for the epochs of July, August, and December 2014. We measured the photometric values in J, H2H3, K1K2 bands for the four planets with a mean accuracy of 0.13 mag. We found upper limit constraints on the mass of a possible planet f of 3-7 M Jup . Our new measurements are more consistent with the two inner planets d and e being in a 2d:1e or 3d:2e resonance. The spectra of HR 8799 d and e are well matched by those of L6-8 field dwarfs. However, the SEDs of these objects are redder than field L dwarfs longward of 1.6 µm.

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“…However, constraints from the stellar properties (Marois et al 2008;Baines et al 2012), the mass of the disk (Su et al 2009), and models of dynamical stability of the four planets (Esposito et al 2013;Goździewski & Migaszewski 2014) suggest that the system is young. Other hints for small radii or low masses of the planets come from the fitting of their spectral energy distribution (e.g., Marois et al 2008;Bowler et al 2010;Currie et al 2011;Barman et al 2011;Madhusudhan et al 2011;Galicher et al 2011;Ingraham et al 2014), although there are uncertainties on the atmospheric composition and the physical processes governing their atmospheres assumed for the models (e.g., solar/non-solar metallicity, physics of the clouds, non-equilibrium chemistry).…”

Section: Constraints On the Properties Of A Fifth Planetmentioning

confidence: 99%

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

Maire

Skemer

Hinz

et al. 2015

A&A

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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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GEMINI PLANET IMAGER SPECTROSCOPY OF THE HR 8799 PLANETS c AND d

Cited by 87 publications

References 34 publications

First light of the VLT planet finder SPHERE

First light of the VLT planet finder SPHERE

First light of the VLT planet finder SPHERE

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

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