Hamilton echelle spectra of young stars. I - Optical veiling

Basri, Gibor; Batalha, C.

doi:10.1086/169374

Cited by 167 publications

(190 citation statements)

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“…To match the science spectrum, the template is then artificially veiled to account for circumstellar disk emission and its absorption lines broadened. This is achieved by adding an excess flat continuum and by convolving the template spectrum with a Gaussian of variable width (for this technique, see also Hartigan et al 1989Hartigan et al , 1991Basri & Batalha 1990). The best fit is found by minimizing the residuals after subtraction of the veiled and broadened template from the science spectrum, over a grid of veiling and broadening values.…”

Section: Photospheric Correction Of M 29 M Spectramentioning

confidence: 99%

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

Banzatti

Pontoppidan

Salyk

et al. 2017

ApJ

121

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We present a new velocity-resolved survey of 2.9 μm spectra of hot H 2 O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ∼ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9-33 μm that probe from the dust sublimation radius at ∼0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H 2 O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (Rco), which probes molecular gaps in inner disks. We find that H 2 O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as R co increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars ofgenerally have inner gaps with depleted molecular gas content. We measure radial trends in H 2 O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05-20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA.

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Section: Photospheric Correction Of M 29 M Spectramentioning

confidence: 99%

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

Banzatti

Pontoppidan

Salyk

et al. 2017

ApJ

121

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“…For each TTS and mainsequence template in our sample, Table 1 gives pertinent stellar information, when the star was observed, and which wavelength settings were observed. Spectral types come, in order of preference, from Basri & Batalha (1990), GHBC, VBJ, Walter et al (1994), andWebb et al (1999). Rotation periods are from Bouvier (1990) and Bouvier et al (1995).…”

Section: Observationsmentioning

confidence: 99%

“…Hot spots would be created by shocks where accreting material strikes the stellar surface. Continuum emission from a hot spot "" veils ÏÏ the stellar spectrum, reducing the residual depth of photospheric absorption lines (Basri & Bertout 1989 ;Basri & Batalha 1990 ;Hartmann & Kenyon 1990 ;Hartigan et al 1991 ;Valenti, Basri, & Johns 1993, hereafter VBJ ;Gullbring et al 1998, hereafter GHBC). Many CTTSs also have redshifted absorption components in their Balmer line proÐles, indicating the presence of infalling material relatively close to the stellar surface (Hartmann 1982 ;Basri 1988 ;Edwards et al 1994 ;Alencar & Basri 2000).…”

Section: Introductionmentioning

confidence: 99%

New Infrared Veiling Measurements and Constraints on Accretion Disk Models for Classical T Tauri Stars

Johns–Krull

Valenti

2001

ApJ

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We analyze K-band infrared (IR) spectra of 14 classical and nine naked T Tauri stars. Using Ðve lines of CO, we determine v sin i and show that IR and optical measurements agree well. From this we conclude that K-band absorption lines generally form in the stellar photosphere. Using line equivalent widths, we measure K-band veiling for classical T Tauri stars in our sample. Accretion disk models constrained by existing stellar and accretion parameters yield testable predictions for K-band veiling. In the context of these models, we examine sources of IR emission from the disk. The importance of disk reprocessing of emission from the accretion shock as material strikes the stellar surface is shown. We then show that current models constrained by the most recent estimates of mass accretion have a difficult time reproducing many of our high-veiling results. We suggest that dust out of the plane of the accretion disk (possibly in the magnetospheric Ñow itself) may account for much of the emission missing in the models.

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“…The strength of the Ha line is often characteristic of strong boundary layer emission arising at the interface of a circumstellar disk and the stellar surface. Veiling from continuum emission may be important (Basri & Batalha 1990) of the absorption features. However, the fact that the forbidden emission lines are so inconspicuous suggests that any circumstellar wind is currently quite weak even though the presence of the HH object implies the existence of a mass outflow on a larger scale.…”

Section: Spectroscopic Observationsmentioning

confidence: 99%

A new Herbig-Haro object in the GUM nebula and its associated star

Graham

1991

PASP

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Photographic and spectroscopic observations are presented of some faint nebulosity which is associated with the strong IRAS point source 08211-4158. Two components are observed. One relatively compact and knotty region has a purely gaseous spectrum characteristic of a low-excitation Herbig-Haro object while another area shows a spectrum with strong continuum radiation and superposed emission lines which suggest that it is scattering light from an embedded young star. Radial-velocity measurements show that this star is at rest with respect to its surroundings while the Herbig-Haro object has a mean velocity of -38 km s -1 with respect to its local standard of rest. The evidence favors but does not conclusively show that the source 1 in the area, identified by Campbell & Persson 1988, marks the position of the embedded star which powers the Herbig-Haro object.

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Hamilton echelle spectra of young stars. I - Optical veiling

Cited by 167 publications

References 0 publications

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

The Depletion of Water During Dispersal of Planet-Forming Disk Regions

New Infrared Veiling Measurements and Constraints on Accretion Disk Models for Classical T Tauri Stars

A new Herbig-Haro object in the GUM nebula and its associated star

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