LATEX TikZposter NEAR-INFRARED VEILING OF ACCRETING STARS USING THE CFHT/SPIROU DATA A. P. Sousa1, J. Bouvier1, S. H. P. Alencar2, J.-F. Donati3, C. Dougados 1, A. Carmona1 and the SPIRou consortium 1Institut de Planétologie et d’Astrophysique de Grenoble - IPAG - France 2Universidade Federal de Minas Gerais - UFMG - Brasil 3Univ. de Toulouse - France alana.sousa@univ-grenoble-alpes.fr NEAR-INFRARED VEILING OF ACCRETING STARS USING THE CFHT/SPIROU DATA A. P. Sousa1, J. Bouvier1, S. H. P. Alencar2, J.-F. Donati3, C. Dougados 1, A. Carmona1 and the SPIRou consortium 1Institut de Planétologie et d’Astrophysique de Grenoble - IPAG - France 2Universidade Federal de Minas Gerais - UFMG - Brasil 3Univ. de Toulouse - France alana.sousa@univ-grenoble-alpes.fr Context Veiling is ubiquitous at different wavelength ranges in classical T Tauri stars (e.g., Hartigan et al. 1991; Fischer et al. 2011). The hot spot alone is not enough to explain the shallow photospheric infrared lines in accreting systems, and it suggests that another source contributes to the veiling in the near-infrared. The inner disk is often quoted as the additional emitting source to explain the infrared veiling (e.g., McClure et al. 2013; Alcalá et al. 2021). We used a sample of accreting stars observed with the CFHT/SPIRou spectrograph to measure the near-infrared veiling along the YJHK bands to understand its origin and time scale variability. We compared the computed veiling with accretion and inner disk diagnostics from photometric observations gathered in the literature. Near-infrared veiling • Additional continuum – accretion shock (hot spot) – dust in the inner disk – gas in the inner disk Sample of stars - CFHT/SPIRou YJHK veiling Fig. 1: Average near-infrared veiling (left), the veiling variability diagnostic (right) measured in different wavelength regions. • Veiling increases with the wavelength from Y to K band in most stars, highlighting the contribution of the inner disk emission to the NIR-veiling. Inner disk emission Fig. 2: Comparison between the color excess computed using the near-infrared veiling and the 2MASS photometry. • The relation between the near-infrared veiling and the inner disk emission diagnostics show that a higher veiled system also presents higher inner disk emission, which is expected if the veiling has a contribution from the inner disk. Short-term variability • Veiling varies in a time scale of at least one day, then what- ever region the NIR-veiling comes from, this region is dy- namic, and its flux changes in a time scale of days. • We computed the periodogram of the veiling, and we did not find any significant periodic signal in the veiling for most systems (in the time scale of typical stellar rotation). Accretion diagnostics Fig. 3: Near-infrared veiling as a function of average mass accretion rate computed using the line fluxes of Paβ and Brγ. • We found a linear correlation between the veiling and the ac- cretion properties of the system. This shows that, although the veiling shows a contribution from the inner disk emis- sion, it also suggests a connection with the accretion process. Conclusion • The veiling increase from the Y to the K band, as a result of the increase of the emission contribution from the inner disk as a function of wavelength. • The veiling correlates with other photometric inner disk di- agnostics, such as color excess and slope of the spectral en- ergy distribution, providing further evidence that the veiling arises in the inner disk. We also find a linear correlation be- tween the veiling and the accretion properties of the system. This shows that accretion contributes to inner disk heating and, consequently, to the inner disk emission excess. • We show that the veiling is variable for most targets in a time scale of at least one day. Besides that, the near-infrared veil- ing seems mostly stable on a long time scale for most targets. Long-term variability Fig. 4: Average of the near-infrared veiling c