Coronagraphic Imaging of Pre–Main‐Sequence Stars with the<i>Hubble Space Telescope</i>Space Telescope Imaging Spectrograph. I. The Herbig Ae Stars

Grady, C. A.; Woodgate, B. E.; Bowers, Charles W.; Gull, Theodore R.; Sitko, Michael L.; Carpenter, W. J.; Lynch, D. K.; Russell, R. W.; Perry, R. B.; Williger, G. M.; Roberge, Aki; Bouret, Jean-Claude; Sahu, M. S.

doi:10.1086/430731

Cited by 58 publications

(69 citation statements)

References 68 publications

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“…Our methods can also be applied to the inner walls of fully cleared inner cavities in transitional disks. If the inner walls are sufficiently puffed up, they can shadow the outer disk and create flat radial surface brightness profiles seen in some disks (Grady et al 2005). Polarized intensity images are a promising way to resolve protoplanetary disks (e.g., Oppenheimer et al 2008), but geometrical effects make these images difficult to interpret (e.g., Jang-Condell & Kuchner 2010; Perrin et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Gaps in Protoplanetary Disks as Signatures of Planets. I. Methodology and Validation

Jang‐Condell

Turner

2012

ApJ

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We examine the observational consequences of partial gaps being opened by planets in protoplanetary disks. We model the disk using a static α-disk model with detailed radiative transfer, parameterizing the shape and size of the partially cleared gaps based on the results of hydrodynamic simulations. Shadowing and illumination by stellar irradiation at the surface of the gap leads to increased contrast as the gap trough is deepened by shadowing and cooling and the far gap wall is puffed up by illumination and heating. In calculating observables, we find that multiple scattering is important and derive an approximation to include these effects. A gap produced by a 200 M ⊕ (70 M ⊕ ) planet at 10 AU can lower/raise the midplane temperature of the disk by up to ∼−25%/+29% (∼−11/+19) by shadowing in the gap trough and illumination on the far shoulder of the gap. At the distance of Taurus, this gap would be resolvable with ∼0. 01 angular resolution. The gap contrast is most significant in scattered light and at thermal continuum wavelengths characteristic of the surface temperature, reducing or raising the surface brightness by up to order of magnitude. Since gap sizes are correlated with planet mass, this is a promising way of finding and determining the masses of planets embedded in protoplanetary disks.

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Section: Discussionmentioning

confidence: 99%

Gaps in Protoplanetary Disks as Signatures of Planets. I. Methodology and Validation

Jang‐Condell

Turner

2012

ApJ

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“…4 (Coulson & Walther 1995). HD 135344B has been observed by the HST in coronographic mode with NICMOS (1.1 and 1.6 μm) and STIS and no companions were found (Grady et al 2005(Grady et al , 2009). The 5σ detection sensitivity limits show the non-existence of stellar companions within ∼0.1 to 1 arcsec (∼14 to 140 AU) from the star.…”

Section: Hd 135344b or Sao 206462mentioning

confidence: 99%

Ruling out unresolved binaries in five transitional disks

Vicente

Merın

Hartung

et al. 2011

A&A

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Context. The presence of unresolved binaries on sub-arsecond scales could explain the existence of optically thin inner holes or gaps in circumstellar disks, which are commonly referred to as "transitional" or "cold" disks, and it is the first scenario to check before making any other assumptions. Aims. We aim at detecting the presence of companions inside the inner hole/gap region of a sample of five well known transitional disks using spatially-resolved imaging in the near-IR with the VLT/NACO/S13 camera, which probes projected distances from the primary of typically 0.1 to 7 arcsec. The sample includes the stars DoAr 21, HD 135344B (SAO 206462), HR 4796A, T Cha, and TW Hya, spanning ages of less than 1 to 10 Myr, spectral types of A0 to K7, and hole/gap outer radii of 4 to 100 AU. Methods. In order to enhance the contrast and to avoid saturation at the core of the point-spread function (PSF), we use narrow-band filters at 1.75 and 2.12 μm. The "locally optimized combination of images" (LOCI) algorithm is applied for an optimal speckle noise removal and PSF subtraction, providing an increase of 0.5-1.5 mag in contrast over the classic method. Results. With the proviso that we could have missed companions owing to unfavorable projections, the VLT/NACO observations rule out the presence of unresolved companions down to an inner radius of about 0. 1 from the primary in all five transitional disks and with a detection limit of 2 to 5 mag in contrast. In the disk outer regions the detection limits typically reach 8 to 9 mag in contrast and 4.7 mag for T Cha. Hence, the NACO images resolve part of the inner hole/gap region of all disks with the exception of TW Hya, for which the inner hole is only 4 AU. The 5σ sensitivity profiles, together with a selected evolutionary model, allow to discard stellar companions within the inner hole/gap region of T Cha, and down to the substellar regime for HD 135344B and HR 4796A. DoAr 21 is the only object from the sample of five disks for which the NACO images are sensitive enough for a detection of objects less massive than ∼13 M Jup that is, potential giant planets or low-mass brown dwarfs at radii larger than ∼76 AU (0. 63). Conclusions. These new VLT/NACO observations further constrain the origin of the inner opacity cavities to be owing to closer or lower-mass companions or other mechanisms such as giant planet formation, efficient grain growth, and photoevaporation (for DoAr 21 and HR 4796A).

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“…It was proposed that in this scenario, the disk structure evolves from flaring (group I) to flat (group II). However, recent studies indicate that almost all group I objects have large dust gaps (Grady et al 2005;Honda et al 2012;Maaskant et al 2013). This implies that it is unlikely that group I Fig.…”

Section: Introductionmentioning

confidence: 99%

Large dust gaps in the transitional disks of HD 100453 and HD 34282

Khalafinejad

Maaskant

Mariñas

et al. 2016

A&A

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Context. The formation of dust gaps in protoplanetary disks is one of the most important signs of disk evolution and might indicate the formation of planets. Aims. We aim to characterize the flaring disk structure around the Herbig Ae/Be stars HD 100453 and HD 34282. Their spectral energy distributions (SEDs) show an emission excess between 15−40 µm, but very weak (HD 100453) and no (HD 34282) signs of the 10 and 20 µm amorphous silicate features. We investigate whether this implies the presence of large dust gaps. Methods. We investigated spatially resolved mid-infrared Q-band images taken with Gemini North/MICHELLE. We performed radiative transfer modeling and examined the radial distribution of dust. We simultaneously fit the Q-band images and SEDs of HD 100453 and HD 34282. Results. Our solutions require that the inner halos and outer disks be separated by large dust gaps that are depleted with respect to the outer disk by a factor of 1000 or more. The inner edges of the outer disks of HD 100453 and HD 34282 have temperatures of ∼160 ± 10 K and ∼60 ± 5 K, respectively. Because of the high surface brightness of these walls, they dominate the emission in the Q band. Their radii are constrained at 20 +2 −2 AU and 92 +31 −17 AU, respectively. Conclusions. HD 100453 and HD 34282 most likely have disk dust gaps. The upper limit of the dust mass in each gap is estimated to be about 10 −7 M . We find that the locations and sizes of disk dust gaps are connected to the SED, as traced by the mid-infrared flux ratio F 30 /F 13.5 . We propose a new classification scheme for the Meeus groups based on the F 30 /F 13.5 ratio. The absence of amorphous silicate features in the observed SEDs is caused by the depletion of small ( 1 µm) silicate dust at temperatures above 160 K, which could be related to the presence of a dust gap in that region of the disk.

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Coronagraphic Imaging of Pre–Main‐Sequence Stars with theHubble Space TelescopeSpace Telescope Imaging Spectrograph. I. The Herbig Ae Stars

Cited by 58 publications

References 68 publications

Gaps in Protoplanetary Disks as Signatures of Planets. I. Methodology and Validation

Gaps in Protoplanetary Disks as Signatures of Planets. I. Methodology and Validation

Ruling out unresolved binaries in five transitional disks

Large dust gaps in the transitional disks of HD 100453 and HD 34282

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