The IGRINS YSO Survey II: Veiling Spectra of Pre-main-sequence Stars in Taurus-Auriga

Kidder, Benjamin; Mace, Gregory N.; López-Valdivia, Ricardo; Sokal, Kimberly R.; Catlett, Victoria; Gutiérrez, Miguel; Tofflemire, Benjamin M.; Jaffe, D. T.

doi:10.3847/1538-4357/ac1dae

Cited by 4 publications

(4 citation statements)

References 71 publications

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“…The Lyα flux ratios and veiling measurements are statistically significantly positively correlated (Spearman ρ = 0.60, p = 0.006), showing that increased veiling generally corresponds to P Cygni-like Lyα emission lines. We also find a strong negative correlation between the H I velocities and the K-band veiling measurements (Spearman ρ = −0.66, p = 0.0006), consistent with the disappearance of T ∼ 2000 K dust that fills in the intrinsic protostellar spectrum (see, e.g., Kidder et al 2021). This may indicate a depletion of inner disk material as outflowing winds slow by shifting to larger radii and infalling accretion flows become the dominant absorber of Lyα photons, although r K may also be influenced by the inner disk inclination or scale height that we cannot measure from these observations (see, e.g., Johns-Krull & Valenti 2001).…”

Section: Model H I Velocities Probe Kinematics Of Accretion and Outflowssupporting

confidence: 80%

Lyα Scattering Models Trace Accretion and Outflow Kinematics in T Tauri Systems*

Arulanantham

Grönke

Fiorellino

et al. 2023

ApJ

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T Tauri stars produce broad Lyα emission lines that contribute ∼88% of the total UV flux incident on the inner circumstellar disks. Lyα photons are generated at the accretion shocks and in the protostellar chromospheres and must travel through accretion flows, winds, and jets, the protoplanetary disks, and the interstellar medium before reaching the observer. This trajectory produces asymmetric, double-peaked features that carry kinematic and opacity signatures of the disk environments. To understand the link between the evolution of Lyα emission lines and the disks themselves, we model HST-COS spectra from targets included in Data Release 3 of the Hubble UV Legacy Library of Young Stars as Essential Standards program. We find that resonant scattering in a simple spherical expanding shell is able to reproduce the high-velocity emission line wings, providing estimates of the average velocities within the bulk intervening H i. The model velocities are significantly correlated with the K-band veiling, indicating a turnover from Lyα profiles absorbed by outflowing winds to emission lines suppressed by accretion flows as the hot inner disk is depleted. Just 30% of targets in our sample have profiles with redshifted absorption from accretion flows, many of which have resolved dust gaps. At this stage, Lyα photons may no longer intersect with disk winds along the path to the observer. Our results point to a significant evolution of Lyα irradiation within the gas disks over time, which may lead to chemical differences that are observable with ALMA and JWST.

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Section: Model H I Velocities Probe Kinematics Of Accretion and Outflowssupporting

confidence: 80%

Lyα Scattering Models Trace Accretion and Outflow Kinematics in T Tauri Systems*

Arulanantham

Grönke

Fiorellino

et al. 2023

ApJ

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“…However, to draw this conclusion, we assumed that these inner disk indicators, such as the slope of the spectral energy distribution, are suitable inner disk diagnostics. Kidder et al (2021) showed that some of the targets classified as Class III using these disk indicators still show some inner disk emission based on the K band excess. They checked the emission excess of V819 Tau, which we used as a template to compute the veiling, but the H and K excesses found were very small, similar to the systematic veiling we obtained in Sect.…”

Section: Veiling Compared To Inner Disk Diagnosticsmentioning

confidence: 99%

“…The veiling in the optical and in the IR wavelengths has been studied using different approaches in the aim to understand its origins and variability (e.g., Basri & Batalha 1990;Edwards et al 2006;Fischer et al 2011;Antoniucci et al 2017;Gully-Santiago et al 2017;Ingleby et al 2013;McClure et al 2013;Kidder et al 2021). The veiling variability along the stellar spectra depends on wavelength (e.g., Fischer et al 2011;Faesi et al 2012;McClure et al 2013;Rei et al 2018), and optical veiling is often associated with the accretion process, while the accretion shock is thought to be at the origin of an additional continuum emitting source to the stellar spectrum.…”

Section: Introductionmentioning

confidence: 99%

New insights on the near-infrared veiling of young stars using CFHT/SPIRou data

Sousa¹,

Bouvier²,

Alencar³

et al. 2023

A&A

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Context. Veiling is ubiquitous at different wavelength ranges in classical T Tauri stars. However, the origin of the veiling in the infrared (IR) domain is not well understood at present. The accretion spot alone is not enough to explain the shallow photospheric IR lines in accreting systems, suggesting that another source is contributing to the veiling in the near-infrared (NIR). The inner disk is often quoted as the additional emitting source meant to explain the IR veiling. Aims. In this work, we aim to measure and discuss the NIR veiling to understand its origins and variability timescale. Methods. We used a sample of 14 accreting stars observed with the CFHT/SPIRou spectrograph, within the framework of the SPIRou Legacy Survey, to measure the NIR veiling along the YJHK bands. We compared the veiling measurements with accretion and inner disk diagnostics. We also analyzed circumstellar emission lines and photometric observations from the literature. Results. The measured veiling grows from the Y to the K band for most of the targets in our sample. The IR veiling agrees with NIR emission excess obtained using photometric data. However, we also find a linear correlation between the veiling and the accretion properties of the system, showing that accretion contributes to the inner disk heating and, consequently, to the inner disk emission excess. We also show a connection between the NIR veiling and the system’s inclination with respect to our line of sight. This is probably due to the reduction of the visible part of the inner disk edge, where the NIR emission excess is expected to arise, as the inclination of the system increases. Our search for periods on the veiling variability showed that the IR veiling is not clearly periodic in the typical timescale of stellar rotation – which, again, is broadly consistent with the idea that the veiling comes from the inner disk region. The NIR veiling appears variable on a timescale of a day, showing the night-by-night dynamics of the optical veiling variability. In the long term, the mean NIR veiling seems to be stable for most of the targets on timescales of a month to a few years. However, during occasional episodes of high accretion in classical T Tauri stars, which affect the system’s dynamic, the veiling also seems to be much more prominent at such times, as we found in the case of the target RU Lup. Conclusions. We provide further evidence that for most targets in our sample, the veiling that mainly occurs in the JHK bands arises from dust in the inner disk.

show abstract

Section: Introductionmentioning

confidence: 99%

New insights on the near-infrared veiling of young stars using CFHT/SPIRou data

Sousa¹,

Bouvier²,

Alencar³

et al. 2023

Preprint

View full text Add to dashboard Cite

Context.Veiling is ubiquitous at different wavelength ranges in classical T Tauri stars. However, the origin of the veiling in the infrared (IR) domain is not well understood at present. The accretion spot alone is not enough to explain the shallow photospheric IR lines in accreting systems, suggesting that another source is contributing to the veiling in the near-infrared (NIR). The inner disk is often quoted as the additional emitting source meant to explain the IR veiling. Aims. In this work, we aim to measure and discuss the NIR veiling to understand its origins and variability timescale. Methods. We used a sample of 14 accreting stars observed with the CFHT/SPIRou spectrograph, within the framework of the SPIRou Legacy Survey, to measure the NIR veiling along the Y JHK bands. We compared the veiling measurements with accretion and inner disk diagnostics. We also analyzed circumstellar emission lines and photometric observations from the literature. Results. The measured veiling grows from the Y to the K band for most of the targets in our sample. The IR veiling agrees with NIR emission excess obtained using photometric data. However, we also find a linear correlation between the veiling and the accretion properties of the system, showing that accretion contributes to the inner disk heating and, consequently, to the inner disk emission excess. We also show a connection between the NIR veiling and the system's inclination with respect to our line of sight. This is probably due to the reduction of the visible part of the inner disk edge, where the NIR emission excess is expected to arise, as the inclination of the system increases. Our search for periods on the veiling variability showed that the IR veiling is not clearly periodic in the typical timescale of stellar rotation -which, again, is broadly consistent with the idea that the veiling comes from the inner disk region. The NIR veiling appears variable on a timescale of a day, showing the night-by-night dynamics of the optical veiling variability. In the long term, the mean NIR veiling seems to be stable for most of the targets on timescales of a month to a few years. However, during occasional episodes of high accretion in classical T Tauri stars, which affect the system's dynamic, the veiling also seems to be much more prominent at such times, as we found in the case of the target RU Lup. Conclusions. We provide further evidence that for most targets in our sample, the veiling that mainly occurs in the JHK bands arises from dust in the inner disk.

show abstract

The IGRINS YSO Survey II: Veiling Spectra of Pre-main-sequence Stars in Taurus-Auriga

Cited by 4 publications

References 71 publications

Lyα Scattering Models Trace Accretion and Outflow Kinematics in T Tauri Systems*

Lyα Scattering Models Trace Accretion and Outflow Kinematics in T Tauri Systems*

New insights on the near-infrared veiling of young stars using CFHT/SPIRou data

New insights on the near-infrared veiling of young stars using CFHT/SPIRou data

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