Two Wide Planetary-Mass Companions to Solar-Type Stars in Upper Scorpius

Ireland, Michael; Kraus, Adam L.; Martinache, Frantz; Law, Nicholas M.; Hillenbrand, Lynne A.

doi:10.1088/0004-637x/726/2/113

Cited by 161 publications

(174 citation statements)

References 67 publications

(78 reference statements)

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“…A&A 562, A127 (2014) very low-mass objects that would be too faint to study once they have aged were rapidly discovered in young clusters and in young nearby (<100 pc) associations (see the review of Torres et al 2008) during deep infrared surveys (e.g., Robberto et al 2010), observation campaigns with adaptive optics devices (e.g. Chauvin et al 2003Chauvin et al , 2010Ireland et al 2011) and with space observatories (Hubble, Spitzer: e.g Lowrance et al 1999Lowrance et al , 2000Lowrance et al , 2005Luhman et al 2007;Todorov et al 2010). Among these discoveries, planetary mass objects ( 13.6 M Jup , see the definition of the International Astronomical Union) were found to be free-floating (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Among these discoveries, planetary mass objects ( 13.6 M Jup , see the definition of the International Astronomical Union) were found to be free-floating (e.g. Oasa et al 1999;Lucas & Roche 2000;Zapatero Osorio et al 2000), orbiting brown dwarfs (2MASSW J1207334-393254, USCO CTIO 108, 2MASS J04414489+2301513; Chauvin et al 2004;Béjar et al 2008;Todorov et al 2010) or as wide (>5 AU) companions to stars (AB Pic, DH Tau, CHXR 73, GQ Lup, CT Cha, Fomalhaut, HR8799, β Pictoris, GSC 06214-00210, 1RXS J235133.3+312720, κ Andromedae; Chauvin et al 2005b;Itoh et al 2005;Luhman et al 2006;Neuhäuser et al 2005;Schmidt et al 2008;Kalas et al 2008;Marois et al 2008Marois et al , 2010Lagrange et al 2010;Ireland et al 2011;Bowler et al 2012;Carson et al 2013), or even binaries (SR 12 AB, 2MASS J01033563-5515561 AB; Kuzuhara et al 2011;Delorme et al 2013). This variety of configurations offers precious benchmarks for planet and brown-dwarf formation models (e.g.…”

Section: Introductionmentioning

confidence: 99%

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A library of near-infrared integral field spectra of young M–L dwarfs

Bonnefoy

Chauvin

Lagrange

et al. 2014

A&A

143

204

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Context. At young ages, low surface gravity affects the atmospheric properties of ultracool dwarfs. The impact on medium-resolution near-infrared (NIR) spectra has only been slightly investigated at the M-L transition so far. Aims. We present a library of NIR (1.1-2.45 µm) medium-resolution (R ∼ 1500-2000) integral field spectra of 15 young M6−L0 dwarfs. We aim at deriving updated NIR spectral type, luminosity, and physical parameters (T eff , log g, M, L/L ) for each source. This work also aims at testing the latest generation of BT-SETTL atmospheric models. Methods. We estimated spectral types using spectral indices and the spectra of young objects classified in the optical. We used the 2010 and 2012 releases of the BT-SETTL synthetic spectral grid and cross-checked the results with the DRIFT-PHOENIX models to derive the atmospheric properties of the sources. Results. We do not find significant differences between the spectra of young companions and those of young isolated brown dwarfs in the same spectral type range. We derive infrared spectral types L0 ± 1, L0 ± 1, M9.5 ± 0.5, M9.5 ± 0.5, M9.25 ± 0.25, M8 +0.5 −0.75 , and M8.5 ± 0.5 for AB Pic b, Cha J110913-773444, USco CTIO 108B, GSC 08047-00232 B, DH Tau B, CT Cha b, and HR7329B, respectively. The BT-SETTL and DRIFT-PHOENIX models yield close T eff and log g estimates for each source. The models seem to show a 600 +600 −300 K drop in the effective temperature at the M-L transition. Assuming the former temperatures are correct, we then derive new mass estimates that confirm that DH Tau B, USco CTIO 108B, AB Pic b, KPNO Tau 4, OTS 44, and Cha1109 lie inside or at the boundary of the planetary mass range. We combine the empirical luminosities of the M9.5-L0 sources to the T eff to derive semi-empirical radii estimates that do not match "hot-start" evolutionary models predictions at 1-3 Myr. We use complementary data to demonstrate that atmospheric models are able to reproduce the combined optical and infrared spectral energy distribution, together with the NIR spectra of these sources simultaneously. But the models still fail to represent the dominant features in the optical. This issue raises doubts on the ability of these models to predict effective temperatures from NIR spectra alone. Conclusions. The library provides templates for characterizing other young and late type objects. The study advocates the use of photometric and spectroscopic information over a broad range of wavelengths to study the properties of very low-mass young companions to be detected with the planet imagers (Subaru/SCExAO, LBT/LMIRCam, Gemini/GPI, VLT/SPHERE).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A library of near-infrared integral field spectra of young M–L dwarfs

Bonnefoy

Chauvin

Lagrange

et al. 2014

A&A

143

204

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“…Advances in high-contrast and high-resolution imaging in the NIR (1-5 µm) led to the discovery of late-type companions to young nearby stars straddling the planet/BD boundary (e.g., Chauvin et al 2004Chauvin et al , 2005Lafrenière et al 2008;Marois et al 2008Marois et al , 2010Lagrange et al 2010;Ireland et al 2011;Delorme et al 2013;Rameau et al 2013;Kuzuhara et al 2013;Currie et al 2014). Most of these objects have estimated effective temperatures similar to those of L dwarfs.…”

Section: Introductionmentioning

confidence: 99%

New constraints on the formation and settling of dust in the atmospheres of young M and L dwarfs

Manjavacas

Bonnefoy

Schlieder

et al. 2014

A&A

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Context. Gravity modifies the spectral features of young brown dwarfs (BDs). A proper characterization of these objects is crucial for the identification of the least massive and latest-type objects in star-forming regions, and to explain the origin(s) of the peculiar spectrophotometric properties of young directly imaged extrasolar planets and BD companions. Aims. We obtained medium-resolution (R ∼ 1500−1700) near-infrared (1.1−2.5 µm) spectra of seven young M9.5-L3 dwarfs classified at optical wavelengths. We aim to empirically confirm the low surface gravity of the objects in the near-infrared. We also test whether self-consistent atmospheric models correctly represent the formation and the settling of dust clouds in the atmosphere of young late-M and L dwarfs. Methods. We used the Infrared Spectrometer And Array Camera (ISAAC) at the Very Large Telescope (VLT) to obtain the spectra of the targets. We compared the spectra to those of mature and young BDs, and to young late-type companions to nearby stars with known ages to identify and study gravity-sensitive features. We computed spectral indices weakly sensitive to the surface gravity to derive near-infrared spectral types. Finally, we found the best fit between each spectrum and synthetic spectra from the BT-Settl 2010 and 2013 atmospheric models. Using the best fit, we derived the atmospheric parameters of the objects and identified which spectral characteristics the models do not reproduce. Results. We confirmed that our objects are young BDs and we found near-infrared spectral types in agreement with the ones determined at optical wavelengths. The spectrum of the L2γ dwarf 2MASSJ232252.99-615127.5 reproduces the spectrum of the planetary mass companion 1RXS J160929.1-210524b well. The BT-Settl models fit the spectra and the 1−5 µm spectral energy distribution of the L0-L3 dwarfs for temperatures between 1600−2000 K. But the models fail to reproduce the shape of the H band and the near-infrared slope of some of our targets. This fact, and the best-fit solutions found with super-solar metallicity, are indicative of a lack of dust, in particular at high altitude, in the cloud models. Conclusions. The modeling of the vertical mixing and of the grain growth will be revised in the next version of the BT-Settl models. These revisions may suppress the remaining non-reproducibilities. Our spectra provide additional templates for the characterization of the numerous young L-type companions that will be detected in the coming years by planet imaging instruments such as VLT/SPHERE, Gemini/GPI, Subaru/SCexAO, and LBTI/LMIRCam.

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“…Good prospects for comparison are presented by the recent discovery of a giant planet orbiting another solar-type star in the same Upper Scorpius association (GSC 06214−00210b; Ireland et al 2011;Bowler et al 2011), with a mass of about 14 Jupiter mass and orbiting at about 300 au. Further observations of these systems at radio wavelengths are strongly encouraged.…”

Section: Rxs1609 Bmentioning

confidence: 99%

Search for 150 MHz radio emission from extrasolar planets in the TIFR GMRT Sky Survey

Sirothia

Étangs

Gopal-Krishna

et al. 2014

A&A

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The ongoing radio continuum TIFR GMRT Sky Survey (TGSS) using the Giant Metrewave Radio Telescope (GMRT) at 150 MHz offers an unprecedented opportunity to undertake a fairly deep search for low-frequency radio emission from nearby extrasolar planets. Currently TGSS images are available for a little over a steradian, encompassing 175 confirmed exoplanetary systems. We have searched for their radio counterparts in the TGSS (150 MHz), supplemented with a search in the NRAO VLA Sky Survey (NVSS) and the VLA FIRST survey at 1.4 GHz. For 171 planetary systems, we find no evidence of radio emission in the TGSS maps, placing a 3σ upper limit between 8.7 mJy and 136 mJy (median ∼24.8 mJy) at 150 MHz. These non-detections include the 55 Cnc system for which we place a 3σ upper limit of 28 mJy at 150 MHz. Nonetheless, for four of the extrasolar planetary systems, we find TGSS radio sources coinciding with or located very close to their coordinates. One of these is 61 Vir: for this system a large radio flux density was predicted in the scenario involving magnetosphere-ionosphere coupling and rotation-induced radio emission. We also found 150 MHz emissions toward HD 86226 and HD 164509, where strong radio emission can be produced by the presence of a massive satellite orbiting a rapidly rotating planet. We also detected 150 MHz emission within a synthesized beam from 1RXS1609 b, a pre-main-sequence star harboring a ∼14 Jupiter mass planet (or a brown dwarf). With a bright X-ray-UV star and a high mass, the planet 1RXS1609 b presents the best characteristics for rotation-induced emissions with high radio power. Deeper high-resolution observations toward these planetary systems are needed to discriminate between the possibilities of background radio-source and radio-loud planets. At 1.4 GHz, radio emission toward the planet-harboring pulsar PSR B1620-26 is detected in the NVSS. Emissions at 1.4 GHz are also detected toward the very-hot-Jupiter WASP-77A b (in the FIRST survey) and the giant planet HD 43197 b in a highly eccentric orbit (in NVSS). We briefly discuss these detections, as well as the non-detection of the vast majority of exoplanets.

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Two Wide Planetary-Mass Companions to Solar-Type Stars in Upper Scorpius

Cited by 161 publications

References 67 publications

A library of near-infrared integral field spectra of young M–L dwarfs

A library of near-infrared integral field spectra of young M–L dwarfs

New constraints on the formation and settling of dust in the atmospheres of young M and L dwarfs

Search for 150 MHz radio emission from extrasolar planets in the TIFR GMRT Sky Survey

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