Subaru Near-Infrared Imaging of Herbig Ae Stars*

Fukagawa, Misato; Tamura, Motohide; Itoh, Yoichi; Oasa, Yumiko; Kudo, Tomoyuki; Hayashi, Saeko S.; Kato, Eri; Ootsubo, Takafumi; Itoh, Yoichi; Shibai, Hiroshi; Hayashi, Masahiko

doi:10.1093/pasj/62.2.347

Cited by 51 publications

(57 citation statements)

References 127 publications

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“…Also no clear indication of SiO gas can be found in the residuals of the IRS spectra. Further, such collisions are less likely in the gas disks found in our sample Fukagawa et al 2010;Brown et al 2012;Andrews et al 2009, and references therein) than in a gas-poor debris disk like HD 172555 since the interaction between disk and planetesimals will dramatically reduce the eccentricity of orbits (Bitsch & Kley 2010).…”

Section: Formation History Of the Forsterite Grainsmentioning

confidence: 82%

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The 69μm forsterite band in spectra of protoplanetary disks. Results from theHerschelDIGIT programme

Sturm

Bouwman

Henning

et al. 2013

A&A

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Context. We have analysed far-infrared spectra of 32 circumstellar disks around Herbig Ae/Be and T Tauri stars obtained within the Herschel key programme Dust, Ice and Gas in Time (DIGIT). The spectra were taken with the Photodetector Array Camera and Spectrometer (PACS) on board the Herschel Space Observatory. In this paper we focus on the detection and analysis of the 69 μm emission band of the crystalline silicate forsterite. Aims. This work aims at providing an overview of the 69 μm forsterite bands present in the DIGIT sample. We use characteristics of the emission band (peak position and FWHM) to derive the dust temperature and to constrain the iron content of the crystalline silicates. With this information, constraints can be placed on the spatial distribution of the forsterite in the disk and the formation history of the crystalline grains. Methods. The 69 μm forsterite emission feature is analysed in terms of position and shape to derive the temperature and composition of the dust by comparison to laboratory spectra of that band. The PACS spectra are combined with existing Spitzer IRS spectra and we compare the presence and strength of the 69 μm band to the forsterite bands at shorter wavelengths. Results. A total of 32 disk sources have been observed. Out of these 32, 8 sources show a 69 μm emission feature that can be attributed to forsterite. With the exception of the T Tauri star AS 205, all of the detections are for disks associated with Herbig Ae/Be stars. Most of the forsterite grains that give rise to the 69 μm bands are found to be warm (∼100-200 K) and iron-poor (less than ∼2% iron). AB Aur is the only source where the emission cannot be fitted with iron-free forsterite requiring approximately 3-4% of iron. Conclusions. Our findings support the hypothesis that the forsterite grains form through an equilibrium condensation process at high temperatures. The large width of the emission band in some sources may indicate the presence of forsterite reservoirs at different temperatures. The connection between the strength of the 69 and 33 μm bands shows that at least part of the emission in these two bands originates fom the same dust grains. We further find that any model that can explain the PACS and the Spitzer IRS observations must take the effects of a wavelength dependent optical depth into account. We find weak indications of a correlation of the detection rate of the 69 μm band with the spectral type of the host stars in our sample. However, the sample size is too small to obtain a definitive result.

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Section: Formation History Of the Forsterite Grainsmentioning

confidence: 82%

“…Harker & Desch 2002). Given that all of our targets are still gas-rich Fukagawa et al 2010;Brown et al 2012;Andrews et al 2009, and references therein), small dust grains should be efficiently heated to high temperatures at disk radii of up to at least ∼10 AU.…”

Section: Formation History Of the Forsterite Grainsmentioning

confidence: 99%

The 69μm forsterite band in spectra of protoplanetary disks. Results from theHerschelDIGIT programme

Sturm

Bouwman

Henning

et al. 2013

A&A

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“…Guimarães et al (2006) Juhász et al 2010). The disk around HD 163296 has been spatially resolved (e.g., Grady et al 2000;Fukagawa et al 2010;Sandell et al 2011;Garufi et al 2014), which is extended to ∼ 440 AU and shows a broken ring structure. Asymmetric supersonic jets associated with HD 163296 are found, which are roughly perpendicular to the disk plane (e.g., Devine et al 2000;Wassell et al 2006).…”

Section: A32 Hd 144432mentioning

confidence: 99%

“…-(1) Alecian et al (2013), (2) Rigliaco et al (2015), (9) Sturm et al (2013), (10) Seok & Li (2015), (11) Maaskant et al (2014), (12) Juhász et al (2010), (13) Fairlamb et al (2015), (14) Mariñas et al (2011), (15) Verhoeff et al (2012), (16) van Boekel et al (2005), (17) Siebenmorgen et al (2000), (18) Hubrig et al (2009), (19) Folsom et al (2012, (20) Fukagawa et al (2010), (21) Seok & Li (2016), (22) Keller et al (2008), (23) Merín et al (2010), (24) Harvey et al (1984), (25) Kóspál et al(2012), (26) Boersma et al (2009), (27) Brown et al (2008), (28) Borges Fernandes et al (2007, (29) Schütz et al (2009), (30) Prato et al (2003), (31) Jeffers et al (2013), (32) Huélamo et al (2011), (33) Casey et al (1998), (34) Pinilla et al (2014), (35) Magazzu et al (1991), (36) Liu et al (2011), (37) …”

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confidence: 99%

Polycyclic Aromatic Hydrocarbons in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars

Seok¹,

Li²

2017

ApJ

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A distinct set of broad emission features at 3. 3, 6.2, 7.7, 8.6, 11.3, and 12.7 µm, is often detected in protoplanetary disks (PPDs). These features are commonly attributed to polycyclic aromatic hydrocarbons (PAHs). We model these emission features in the infrared spectra of 69 PPDs around 14 T Tauri and 55 Herbig Ae/Be stars in terms of astronomical-PAHs. For each PPD, we derive the size distribution and the charge state of PAHs. We then examine the correlations of the PAH properties (i.e., sizes and ionization fractions) with the stellar properties (e.g., stellar effective temperature, luminosity, and mass). We find that the characteristic size of PAHs shows a tendency of correlating with the stellar effective temperature (T eff ) and interpret this as the preferential photodissociation of small PAHs in systems with higher T eff of which the stellar photons are more energetic. In addition, the PAH size shows a moderate correlation with the red-ward wavelength-shift of the 7.7 µm PAH feature that is commonly observed in disks around cool stars. The ionization fraction of PAHs does not seem to correlate with any stellar parameters. This is because the charging of PAHs depends on not only the stellar properties (e.g., T eff , luminosity) but also the spatial distribution of PAHs in the disks. The mere negative correlation between the PAH size and the stellar age suggests that continuous replenishment of PAHs via the outgassing of cometary bodies and/or the collisional grinding of planetesimals and asteroids is required to maintain the abundance of small PAHs against complete destruction by photodissociation.

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“…Considering the spectral type, the A7 III source HD 142666 is a Herbig Ae/Be object while the other two sources are T Tauri objects. HD 142666 is assumed not to have any stellar companion (e.g., Fukagawa et al 2010). Considering our interferometric measurements, a sinusoidal visibility spectrum could not be found that would be characteristic of a close (stellar) companion in both systems.…”

Section: Object Samplementioning

confidence: 99%

Multiwavelength interferometric observations and modeling of circumstellar disks

Schegerer

Ratzka

Schuller

et al. 2013

A&A

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Aims. We investigate the structure of the innermost region of three circumstellar disks around pre-main sequence stars HD 142666, AS 205 N, and AS 205 S. We determine the inner radii of the dust disks and, in particular, search for transition objects where dust has been depleted and inner disk gaps have formed at radii of a few tenths of AU up to several AU. Methods. We performed interferometric observations with IOTA, AMBER, and MIDI in the infrared wavelength ranges 1.6−2.5 μm and 8−13 μm with projected baseline lengths between 25 m and 102 m. The data analysis was based on radiative transfer simulations in 3D models of young stellar objects (YSOs) to reproduce the spectral energy distribution and the interferometric visibilities simultaneously. Accretion effects and disk gaps could be considered in the modeling approach. Results from previous studies restricted the parameter space. Results. The objects of this study were spatially resolved in the infrared wavelength range using the interferometers. Based on these observations, a disk gap could be found for the source HD 142666 that classifies it as transition object. There is a disk hole up to a radius of R in = 0.30 AU and a (dust-free) ring between 0.35 AU and 0.80 AU in the disk of HD 142666. The classification of AS 205 as a system of classical T Tauri stars could be confirmed using the canonical model approach, i.e., there are no hints of disk gaps in our observations.

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Subaru Near-Infrared Imaging of Herbig Ae Stars*

Cited by 51 publications

References 127 publications

The 69μm forsterite band in spectra of protoplanetary disks. Results from theHerschelDIGIT programme

The 69μm forsterite band in spectra of protoplanetary disks. Results from theHerschelDIGIT programme

Polycyclic Aromatic Hydrocarbons in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars

Multiwavelength interferometric observations and modeling of circumstellar disks

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