Accretion variability in RU Lup
arXiv:2210.14134 · doi:10.1051/0004-6361/202244315
Abstract
The process of accretion in classical T Tauri stars (CTTSs) has been observed to vary on different timescales. Studying this variability is vital to understanding a star's evolution and provides insight into the complex processes at work within. Understanding the dichotomy between continuum veiling and emission line veiling is integral to accurately measuring the amount of veiling present in stellar spectra. Here, 15 roughly consecutive nights of optical spectroscopic data from the spectropolarimeter ESPaDOnS are utilised to characterise the short-term accretion activity in the CTTS, RU Lup, and investigate its relationship with the veiling in the LiI 6707A absorption line. The accretion-tracing HI Balmer series emission lines were studied and used to obtain the accretion luminosity (Lacc) and mass accretion rate (Macc) for each night, which vary by a factor of ~2 between the brightest and dimmest nights. We also measured the veiling using multiple photospheric absorption lines (NaI 5688A, MnI 6021A, and LiI 6707A) for each night. We find the LiI 6707A line provides measurements of veiling that produce a strong, positive correlation with Lacc in the star. When corrected for Li depletion, the average veiling measured in the LiI 6707A line is r_LiI(avg)~3.25+/-0.20, which is consistent with the other photospheric lines studied (r_avg~3.28+/-0.65). We measured short timescale variability in the Lacc and Macc that are intrinsic and not due to geometric effects. Upon comparing the changes in veiling and Lacc, we find a strong, positive correlation. This study provides an example of how this correlation can be used as a tool to determine whether a measured variability is due to extinction or an intrinsic change in accretion. As the determination of veiling is an independent process from measuring Lacc, their relationship allows further exploration of accretion phenomena in young stars.
16 pages, 13 figures, 4 tables. (including appendicies)
References in corpus (20)
- X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
- UV excess measures of accretion onto young very low-mass stars and brown dwarfs
- Accretion in the Rho-Oph pre-main sequence stars
- Accretion to Magnetized Stars through the Rayleigh-Taylor Instability: Global Three-Dimensional Simulations
- Mapping accretion and its variability in the young open cluster NGC 2264: a study based on u-band photometry
- Tracing Slow Winds from T Tauri Stars via Low Velocity Forbidden Line Emission
- Temperaments of young stars: Rapid mass-accretion rate changes in T Tauri and Herbig Ae stars
- The Gaia-ESO Survey: Chromospheric Emission, Accretion Properties, and Rotation in Velorum and Chamaeleon I
- Young Stellar Object Variability (YSOVAR): Long Timescale Variations in the Mid-Infrared
- Protoplanetary disc evolution affected by star-disc interactions in young stellar clusters
- Unveiling extremely veiled T Tauri stars
- POISSON project - III - Investigating the evolution of the mass accretion rate
- Periodic radial velocity variations in RU Lupi
- An assessment of Li abundances in weak-lined and classical T Tauri stars of the Taurus-Auriga association
- The GRAVITY Young Stellar Object survey. VII. The inner dusty disks of T Tauri stars
- Evidence for an MHD disk wind via optical forbidden line spectro-astrometry
- Measuring the Density Structure of an Accretion Hot Spot
- The magnetic obliquity of accreting T Tauri stars
- X-shooter spectroscopy of young stellar objects in Lupus: Lithium, iron, and barium elemental abundances
- Accretion variability from minutes to decade timescales in the classical T Tauri star CR Cha