Tracing the Inner Edge of the Disk Around Hd 100546 With Rovibrational Co Emission Lines

Brittain, S.; Najita, J.; Carr, John S.

doi:10.1088/0004-637x/702/1/85

Cited by 92 publications

(183 citation statements)

References 54 publications

(120 reference statements)

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“…It was identified by Bouwman et al (2003) as a transitional disk on the basis of its SED even before the term existed, with an estimated companion mass of ∼10 M Jup . The gap was later confirmed using mid-infrared nulling interferometry (Liu et al 2003), UV spectroscopy (Grady et al 2005), nearinfrared CO spectroscopy (Brittain et al 2009;Van Der Plas et al 2009), and mid-infrared interferometry (Panić et al 2012), all 1 consistent with a gap outer radius in the range of 10 to 15 AU. The inner disk is depleted in dust by a few orders of magnitude (Benisty et al 2010;Mulders et al 2011), and is smaller than 0.7 AU in size (Panić et al 2012).…”

Section: Introductionmentioning

confidence: 78%

Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry

Mulders

Paardekooper

Panić

et al. 2013

A&A

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Context. Giant planets form in protoplanetary disks while these disks are still gas-rich, and can reveal their presence through the annular gaps they carve out. HD 100546 is a gas-rich disk with a wide gap between a radius of ∼1 and 13 AU, possibly cleared out by a planetary companion or planetary system. Aims. We aim to identify the nature of the unseen companion near the far end of the disk gap. Methods. We used mid-infrared interferometry at multiple baselines to constrain the curvature of the disk wall at the far end of the gap. We used 2D hydrodynamical simulations of embedded planets and brown dwarfs to estimate the viscosity of the disk and the mass of a companion close to the disk wall. Results. We find that the disk wall at the far end of the gap is not vertical, but rounded-off by a gradient in the surface density. This gradient can be reproduced in hydrodynamical simulations with a single, heavy companion ( 30 . . . 80 M Jup ) while the disk has a viscosity of at least α 5 × 10 −3 . Taking into account the changes in the temperature structure after gap opening reduces the lower limit on the planet mass and disk viscosity to 20 M Jup and α = 2 × 10 −3 . Conclusions. The object in the disk gap of HD 100546 that shapes the disk wall is most likely a 60 +20 −40 M Jup brown dwarf, while the disk viscosity is estimated to be at least α = 2 × 10 −3 . The disk viscosity is an important factor in estimating planetary masses from disk morphologies: more viscous disks need heavier planets to open an equally deep gap.

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Section: Introductionmentioning

confidence: 78%

Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry

Mulders

Paardekooper

Panić

et al. 2013

A&A

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“…We will investigate these effects in a forthcoming paper using a more sophisticated thermal disk model. CO exists inside the dust sublimation radius in some T Tauri stars (Carr 2007) or Herbig Ae/Be stars (Brittain et al 2009), where the disk is optically thin in the absence of dust. One possibility to excite CO in the optically thin inner disk close to the stellar surface is the UV fluorescence, which is far from LTE (Krotkov et al 1980) applied in our calculations.…”

Section: Discussionmentioning

confidence: 99%

“…The UV pumping requires considerable UV flux from the central star, which is a characteristic of Herbig Ae/Be stars rather than smaller T Tauri stars. Considering that the CO may be excited up to to 10 AU by UV fluorescence (Brittain et al 2007(Brittain et al , 2009 in Hebig Ae/Be stars, planet orbiting at larger distances than 2 AU may be also detectable by CO ro-vibrational line profile distortions.…”

Section: Discussionmentioning

confidence: 99%

“…If the distorting effect is strong enough, the line profile distortion could be significant to be detected by high-resolution spectroscopic observations. Indeed several T Tauri stars show symmetric but centrally peaked CO line profiles that can be explained by radially extent CO emission overriding the double peaks (Najita et al 2003;Brittain et al 2009). Stronger CO emission can be expected if UV fluorescence plays a role (Krotkov et al 1980), or the gas temperature is not well coupled to the dust (Kamp & Dullemond 2004;Glassgold et al 2004).…”

Section: Disk Modelsmentioning

confidence: 99%

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Detectability of giant planets in protoplanetary disks by CO emission lines

Regály

Sándor

Dullemond

et al. 2010

A&A

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Context. Planets are thought to form in protoplanetary accretion disks around young stars. Detecting a giant planet still embedded in a protoplanetary disk would be very important and give observational constraints on the planet-formation process. However, detecting these planets with the radial velocity technique is problematic owing to the strong stellar activity of these young objects. Aims. We intend to provide an indirect method to detect Jovian planets by studying near infrared emission spectra originating in the protoplanetary disks around T Tauri stars. Our idea is to investigate whether a massive planet could induce any observable effect on the spectral lines emerging in the disks atmosphere. As a tracer molecule we propose CO, which is excited in the ro-vibrational fundamental band in the disk atmosphere to a distance of ∼2−3 AU (depending on the stellar mass) where terrestrial planets are thought to form. Methods. We developed a semi-analytical model to calculate synthetic molecular spectral line profiles in a protoplanetary disk using a double layer disk model heated on the outside by irradiation by the central star and in the midplane by viscous dissipation due to accretion. 2D gas dynamics were incorporated in the calculation of synthetic spectral lines. The motions of gas parcels were calculated by the publicly available hydrodynamical code FARGO which was developed to study planet-disk interactions. Results. We demonstrate that a massive planet embedded in a protoplanetary disk strongly influences the originally circular Keplerian gas dynamics. The perturbed motion of the gas can be detected by comparing the CO line profiles in emission, which emerge from planet-bearing to those of planet-free disk models. The planet signal has two major characteristics: a permanent line profile asymmetry, and short timescale variability correlated with the orbital phase of the giant planet. We have found that the strength of the asymmetry depends on the physical parameters of the star-planet-disk system, such as the disk inclination angle, the planetary and stellar masses, the orbital distance, and the size of the disk inner cavity. The permanent line profile asymmetry is caused by a disk in an eccentric state in the gap opened by the giant planet. However, the variable component is a consequence of the local dynamical perturbation by the orbiting giant planet. We show that a forming giant planet, still embedded in the protoplanetary disk, can be detected using contemporary or future high-resolution near-IR spectrographs like VLT/CRIRES and ELT/METIS.

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“…In the last few years, observations with the Spitzer Space Telescope have revealed a rich chemistry in the inner few astronomical units (AU) of disks around low-mass stars, containing high abundances of HCN, C 2 H 2 , CO 2 , H 2 O and OH (Lahuis et al 2006a;Salyk et al 2008Salyk et al , 2011aPascucci et al 2009;Kruger et al 2011;Najita et al 2010;Pontoppidan et al 2010). Spectrally and spatially resolved data of CO using ground-based infrared telescopes at 4.7 μm show that the warm molecular gas is indeed associated with the disk (e.g., Najita et al 2003;Brittain et al 2003Brittain et al , 2007Brittain et al , 2009Blake & Boogert 2004;Pontoppidan et al 2008;Salyk et al 2011b;Brown et al 2012), with in some cases an additional contribution from a disk wind (Bast et al 2011;Pontoppidan et al 2011). Spectrally resolved ground-based observations have Appendices are available in electronic form at http://www.aanda.org also been obtained of OH and H 2 O at 3 μm (Carr et al 2004;Mandell et al 2008;Salyk et al 2008;Fedele et al 2011), and most recently of HCN and C 2 H 2 (Gibb et al 2007;Doppmann et al 2008;Mandell et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Exploring organic chemistry in planet-forming zones

Bast

Lahuis

Dishoeck

et al. 2013

A&A

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Context. Over the last few years, the chemistry of molecules other than CO in the planet-forming zones of disks is starting to be explored with Spitzer and high-resolution ground-based data. However, these studies have focused only on a few simple molecules. Aims. The aim of this study is to put observational constraints on the presence of more complex organic and sulfur-bearing molecules predicted to be abundant in chemical models of disks and to simulate high resolution spectra in view of future missions. Methods. High signal-to-noise ratio (S/N) Spitzer spectra of the near edge-on disks IRS 46 and GV Tau are used to search for midinfrared absorption bands of various molecules. These disks are good laboratories because absorption studies do not suffer from low line/continuum ratios that plague emission data. Simple local thermodynamic equilibrium (LTE) slab models are used to infer column densities (or upper limits) and excitation temperatures. Results. Mid-infrared bands of HCN, C 2 H 2 and CO 2 are clearly detected toward both sources. The HCN and C 2 H 2 absorption arises in warm gas with excitation temperatures of 400−700 K, whereas the CO 2 absorption originates in cooler gas of ∼250 K. Column densities and their ratios are comparable for the two sources. No other absorption features are detected at the 3σ level. Column density limits of the majority of molecules predicted to be abundant in the inner disk -C 2 H 4 , C 2 H 6 , C 6 H 6 , C 3 H 4 , C 4 H 2 , CH 3 , HNC, HC 3 N, CH 3 CN, NH 3 and SO 2 -are determined and compared with disk models. Conclusions. The inferred abundance ratios and limits with respect to C 2 H 2 and HCN are roughly consistent with models of the chemistry in high temperature gas. Models of UV irradiated disk surfaces generally agree better with the data than pure X-ray models. The limit on NH 3 /HCN implies that evaporation of NH 3 -containing ices is only a minor contributor. The inferred abundances and their limits also compare well with those found in comets, suggesting that part of the cometary material may derive from warm inner disk gas. The high resolution simulations show that future instruments on the James Webb Space Telescope (JWST), the Extremely Large Telescopes (ELTs), the Stratospheric Observatory for Infrared Astronomy (SOFIA) and the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) can probe up to an order of magnitude lower abundance ratios and put important new constraints on the models, especially if pushed to high S/Ns.

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Tracing the Inner Edge of the Disk Around Hd 100546 With Rovibrational Co Emission Lines

Cited by 92 publications

References 54 publications

Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry

Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry

Detectability of giant planets in protoplanetary disks by CO emission lines

Exploring organic chemistry in planet-forming zones

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