Star-disk interactions in the strongly accreting T Tauri Star S CrA N

Abstract

Aims : We aimed at constraining the accretion-ejection phenomena around the strongly-accreting Northern component of the S CrA young binary system (S CrA N) by deriving its magnetic field topology and its magnetospheric properties, and by detecting ejection signatures, if any. Methods : We led a two-week observing campaign on S CrA N with the ESPaDOnS optical spectropolarimeter at the Canada-France-Hawaii Telescope. We recorded 12 Stokes I and V spectra over 14 nights. We computed the corresponding Least-Square Deconvolution (LSD) profiles of the photospheric lines and performed Zeeman-Doppler Imaging (ZDI). We analysed the kinematics of noticeable emission lines, namely He I $\lambda 5876$ and the four first lines of the Balmer series, known to trace the accretion process. Conclusions : The findings from spectropolarimetry are complementary to those provided by optical long-baseline interferometry, allowing us to construct a coherent view of the innermost regions of a young, strongly accreting star. Yet, the strong and complex magnetic field reconstructed for S CrA N is inconsistent with the observed magnetic signatures of the emission lines associated to the post-shock region. We recommend a multi-technique, synchronized campaign of several days to put more constrains on a system that varies on a $\sim$ 1 day timescale.

References in corpus (22)

• Gaia Data Release 3: Summary of the content and survey properties
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• Accretion to Magnetized Stars through the Rayleigh-Taylor Instability: Global Three-Dimensional Simulations
• A Classification Scheme for Young Stellar Objects Using the WIDE-FIELD INFRARED SURVEY EXPLORER AllWISE Catalog: Revealing Low-Density Star Formation in the Outer Galaxy
• CESAM: a free code for stellar evolution calculations
• Accretion funnels onto weakly magnetized young stars
• The evolution of surface magnetic fields in young solar-type stars II: The early main sequence (250-650 Myr)
• ALMA survey of Class II protoplanetary disks in Corona Australis: a young region with low disk masses
• PENELLOPE: the ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES) I. Survey presentation and accretion properties of Orion OB1 and $\sigma$-Orionis
• The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results
• Self-consistent evolution of accreting low-mass stars and brown dwarfs
• The magnetic field and accretion regime of CI Tau
• Corona-Australis DANCe. I. Revisiting the census of stars with Gaia-DR2 data
• A measure of the size of the magnetospheric accretion region in TW Hydrae
• The GRAVITY Young Stellar Object survey. VII. The inner dusty disks of T Tauri stars
• GIARPS High-resolution Observations of T Tauri stars (GHOsT). III. A pilot study of stellar and accretion properties
• New insights on the near-infrared veiling of young stars using CFHT/SPIRou data
• Star-disk interaction in the T Tauri star V2129 Oph: An evolving accretion-ejection structure
• PENELLOPE IV. A comparison between optical forbidden lines and ${\mathrm{H}}_2$ UV lines in the Orion OB1b and $\sigma$-Ori associations
• The Surface Magnetic Activity of the Weak-Line T Tauri Stars TWA 7 and TWA 25

Cited by in corpus (4)

• A multi-kiloGauss magnetic field driving the magnetospheric accretion process in EX Lupi
• Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau
• The GRAVITY young stellar object survey XIV : Investigating the magnetospheric accretion-ejection processes in S CrA N
• Magnetic field measurements in a sample of Class I and flat-spectrum protostars observed with SPIRou