The Extremely Red, Young L Dwarf Pso J318.5338–22.8603: A Free-Floating Planetary-Mass Analog to Directly Imaged Young Gas-Giant Planets

Liu, Mengmeng; Magnier, E. A.; Deacon, N. R.; Allers, Katelyn; Dupuy, Trent J.; Kotson, Michael C.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K.; Draper, P. W.; Hodapp, Klaus W.; Jedicke, Robert; Kaiser, N.; Kudritzki, Rolf‐Peter; Metcalfe, N.; Morgan, J. S.; Price, P. A.; Tonry, J.; Wainscoat, R. J.

doi:10.1088/2041-8205/777/2/l20

Cited by 253 publications

(272 citation statements)

References 51 publications

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“…The implication is that these young planets have retained their dusty, methane-poor atmospheres at lower luminosities than old field brown dwarfs, which transition to methane-rich, cloud-free Tdwarfs below M H ∼14 mag. Surveys have now found young, dusty brown dwarfs that are more analogous to the HR 8799 planets (e.g., Faherty et al 2013;Liu et al 2013;Gauza et al 2015), and there are theoretical justifications for why, in addition to effective temperature, an objectʼs mass/surface gravity affects the clouds and chemistry of its photosphere Zahnle & Marley 2014).…”

Section: Discussion: Gj 504 B's Unusual Appearancementioning

confidence: 99%

THE LEECH EXOPLANET IMAGING SURVEY: CHARACTERIZATION OF THE COLDEST DIRECTLY IMAGED EXOPLANET, GJ 504 b, AND EVIDENCE FOR SUPERSTELLAR METALLICITY*

Skemer

Morley

Zimmerman

et al. 2016

ApJ

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As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition from L to T, which encompasses the dissipation of cloud opacity and the appearance of strong methane absorption. While there are hundreds of known T-type brown dwarfs, the first generation of directly imaged exoplanets were all Ltype. Recently, Kuzuhara et al. announced the discovery of GJ 504 b, the first T dwarf exoplanet. GJ 504 b provides a unique opportunity to study the atmosphere of a new type of exoplanet with a ∼500 K temperature that bridges the gap between the first directly imaged planets (∼1000 K) and our own solar systemʼs Jupiter (∼130 K). We observed GJ 504 b in three narrow L-band filters (3.71, 3.88, and 4.00 μm), spanning the red end of the broad methane fundamental absorption feature (3.3 μm) as part of the LBTI Exozodi Exoplanet Common Hunt (LEECH) exoplanet imaging survey. By comparing our new photometry and literature photometry with a grid of custom model atmospheres, we were able to fit GJ 504 bʼs unusual spectral energy distribution for the first time. We find that GJ 504 b is wellfit by models with the following parameters:.12, cloud opacity parameter of f sed =2-5, R=0.96±0.07 R Jup , and log(L)=−6.13±0.03 L e , implying a hot start mass of 3-30 M jup for a conservative age range of 0.1-6.5 Gyr. Of particular interest, our model fits suggest that GJ 504 b has a superstellar metallicity. Since planet formation can create objects with nonstellar metallicities, while binary star formation cannot, this result suggests that GJ 504 b formed like a planet, not like a binary companion.

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Section: Discussion: Gj 504 B's Unusual Appearancementioning

confidence: 99%

THE LEECH EXOPLANET IMAGING SURVEY: CHARACTERIZATION OF THE COLDEST DIRECTLY IMAGED EXOPLANET, GJ 504 b, AND EVIDENCE FOR SUPERSTELLAR METALLICITY*

Skemer

Morley

Zimmerman

et al. 2016

ApJ

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“…These might include unusually blue objects, such as SDSS J074656.83+251019.0 (discussed above), or unusually red objects (Faherty et al 2013;Liu et al 2013). Such a population would have a significant influence, e.g.…”

Section: Possible Sources Of Bias In the Colour Relationsmentioning

confidence: 99%

Photometric brown-dwarf classification

Skrzypek

Warren

Faherty

et al. 2015

A&A

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Aims. We present a method, named photo-type, to identify and accurately classify L and T dwarfs onto the standard spectral classification system using photometry alone. This enables the creation of large and deep homogeneous samples of these objects efficiently, without the need for spectroscopy. Methods. We created a catalogue of point sources with photometry in 8 bands, ranging from 0.75 to 4.6 μm, selected from an area of 3344 deg 2 , by combining SDSS, UKIDSS LAS, and WISE data. Sources with 13.0 < J < 17.5, and Y − J > 0.8, were then classified by comparison against template colours of quasars, stars, and brown dwarfs. The L and T templates, spectral types L0 to T8, were created by identifying previously known sources with spectroscopic classifications, and fitting polynomial relations between colour and spectral type. Results. Of the 192 known L and T dwarfs with reliable photometry in the surveyed area and magnitude range, 189 are recovered by our selection and classification method. We have quantified the accuracy of the classification method both externally, with spectroscopy, and internally, by creating synthetic catalogues and accounting for the uncertainties. We find that, brighter than J = 17.5, photo-type classifications are accurate to one spectral sub-type, and are therefore competitive with spectroscopic classifications. The resultant catalogue of 1157 L and T dwarfs will be presented in a companion paper.

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“…Sample 2 is composed of spectra of M and L dwarfs with features indicative of low surface gravity (Allers & Liu 2013;Manjavacas et al 2014;Liu et al 2013;Schneider et al 2014). The third sample is made of spectra of members of 1−150 Myr old young moving groups and clusters (Lodieu et al 2008;Rice et al 2010;Bonnefoy et al 2014;Gagné et al 2014).…”

Section: Appendix A: Details On the Orbital Fitmentioning

confidence: 99%

Physical and orbital properties ofβPictoris b

Bonnefoy

Marleau

Galicher

et al. 2014

A&A

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The intermediate-mass star β Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8−10 AU. The physical properties of β Pic b were previously inferred from broad-and narrow-band 0.9−4.8 µm photometry. We used commissioning data of the Gemini Planet Imager (GPI) to obtain new astrometry and a lowresolution (R ∼ 35−39) J-band (1.12−1.35 µm) spectrum of the planet. We find that the planet has passed the quadrature. We constrain its semi-major axis to ≤10 AU (90% prob.) with a peak at 8.9 +0.4 −0.6 AU. The joint fit of the planet astrometry and the most recent radial velocity measurements of the star yields a planet dynamical mass lower than 20 M Jup (≥96% prob.). The extracted spectrum of β Pic b is similar to those of young L1 +1 −1.5 dwarfs. We used the spectral type estimate to revise the planet luminosity to log(L/L ) = −3.90±0.07. The 0.9−4.8 µm photometry and spectrum are reproduced for T eff = 1650 ± 150 K and a log g ≤ 4.7 dex by 12 grids of PHOENIX-based and LESIA atmospheric models. For the most recent system age estimate (21 ± 4 Myr), the bolometric luminosity and the constraints on the dynamical mass of β Pic b are only reproduced by warm-and hot-start tracks with initial entropies S i > 10.5 k B /baryon. These initial conditions may result from an inefficient accretion shock and/or a planetesimal density at formation higher than in the classical core-accretion model. Considering a younger age for the system or a conservative formation time for β Pic b does not change these conclusions.

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The Extremely Red, Young L Dwarf Pso J318.5338–22.8603: A Free-Floating Planetary-Mass Analog to Directly Imaged Young Gas-Giant Planets

Cited by 253 publications

References 51 publications

THE LEECH EXOPLANET IMAGING SURVEY: CHARACTERIZATION OF THE COLDEST DIRECTLY IMAGED EXOPLANET, GJ 504 b, AND EVIDENCE FOR SUPERSTELLAR METALLICITY*

THE LEECH EXOPLANET IMAGING SURVEY: CHARACTERIZATION OF THE COLDEST DIRECTLY IMAGED EXOPLANET, GJ 504 b, AND EVIDENCE FOR SUPERSTELLAR METALLICITY*

Photometric brown-dwarf classification

Physical and orbital properties ofβPictoris b

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