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

Abstract

Veiling is ubiquitous at different wavelength ranges in accreting stars. However, the origin of the veiling in the IR domain is not well understood. 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 NIR. The inner disk is often quoted as the additional emitting source meant to explain the IR veiling. In this work, we aim to measure and discuss the NIR veiling to understand its origins and variability timescale, using a sample of 14 accreting stars observed with the CFHT/SPIRou spectrograph, within the framework of the SPIRou Legacy Survey. We compared the veiling measurements with accretion and inner disk diagnostics. 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. 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, 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.

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Cited by in corpus (8)

• The ESO SupJup Survey II: The 12C/13C ratios of three young brown dwarfs with CRIRES${}^{+}$
• The ESO SupJup Survey IV. Unveiling the carbon isotope ratio of GQ Lup B and its host star
• The GRAVITY young stellar object survey -- XI. Probing the inner disk and magnetospheric accretion region of CI Tau
• Stable accretion and episodic outflows in the young transition disk system GM Aurigae
• Long period modulation of the classical T Tauri star CI Tau: evidence for an eccentric close-in massive planet at 0.17 au
• Empirical Determination of the Lithium 6707.856 Å Wavelength in Young Stars
• Star-disk interactions in the strongly accreting T Tauri Star S CrA N
• Magnetic field measurements in a sample of Class I and flat-spectrum protostars observed with SPIRou