The close T Tauri binary system V4046 Sgr: Rotationally modulated X-ray emission from accretion shocks

Abstract

We report initial results from a quasi-simultaneous X-ray/optical observing campaign targeting V4046 Sgr, a close, synchronous-rotating classical T Tauri star (CTTS) binary in which both components are actively accreting. V4046 Sgr is a strong X-ray source, with the X-rays mainly arising from high-density (n_e ~ 10^(11-12) cm^(-3)) plasma at temperatures of 3-4 MK. Our multiwavelength campaign aims to simultaneously constrain the properties of this X-ray emitting plasma, the large scale magnetic field, and the accretion geometry. In this paper, we present key results obtained via time-resolved X-ray grating spectra, gathered in a 360 ks XMM-Newton observation that covered 2.2 system rotations. We find that the emission lines produced by this high-density plasma display periodic flux variations with a measured period, 1.22+/-0.01 d, that is precisely half that of the binary star system (2.42 d). The observed rotational modulation can be explained assuming that the high-density plasma occupies small portions of the stellar surfaces, corotating with the stars, and that the high-density plasma is not azimuthally symmetrically distributed with respect to the rotational axis of each star. These results strongly support models in which high-density, X-ray-emitting CTTS plasma is material heated in accretion shocks, located at the base of accretion flows tied to the system by magnetic field lines.

paper accepted by ApJ

References in corpus (15)

• X-Ray Spectroscopy of Stars
• X-ray irradiated protoplanetary disk atmospheres I: Predicted emission line spectrum and photoevaporation
• X-ray emission from MP Muscae: an old classical T Tauri star
• X-ray emission from classical T Tauri stars: Accretion shocks and coronae?
• X-rays from T Tau: A test case for accreting T Tauri stars
• The close classical T Tauri binary V4046 Sgr: Complex magnetic fields & distributed mass accretion
• The X-ray soft excess in classical T Tauri stars
• X-rays from RU Lupi - Accretion and winds in CTTS
• X-ray emission from dense plasma in CTTSs: Hydrodynamic modeling of the accretion shock
• X-ray accretion signatures in the close CTTS binary V4046 Sgr
• Evidence for Accretion in the High-resolution X-ray Spectrum of the T Tauri Star System Hen 3-600
• TW Hya: Spectral Variability, X-Rays, and Accretion Diagnostics
• Molecules in the disk orbiting the twin young suns of V4046 Sgr
• GSC 07396-00759 = V4046 Sgr C[D]: a Wide-separation Companion to the Close T Tauri Binary System V4046 Sgr AB
• On X-ray Optical Depth in the Coronae of Active Stars

Cited by in corpus (26)

• Can we predict the global magnetic topology of a pre-main sequence star from its position in the Hertzsprung-Russell diagram?
• The Structure of the Evolved Circumbinary Disk around V4046 Sgr
• Hot Gas Lines in T Tauri Stars
• Search for associations containing young stars (SACY). V. Is multiplicity universal? Tight multiple systems
• A Subarcsecond ALMA Molecular Line Imaging Survey of the Circumbinary, Protoplanetary Disk Orbiting V4046 Sgr
• Direct Measurement of Interstellar Extinction Toward Young Stars Using Atomic Hydrogen Lyman-$\alpha$ Absorption
• X-ray variability of PMS stars - Toward an explanation of the different X-ray properties of CTTS and WTTS
• Scattered Light from Dust in the Cavity of the V4046 Sgr Transition Disk
• Redshifted X-rays from the material accreting onto TW Hya: evidence of a low-latitude accretion spot
• CSI 2264: Simultaneous optical and X-ray variability in pre-Main Sequence stars. I: Time resolved X-ray spectral analysis during optical dips and accretion bursts in stars with disks
• Impacts of fragmented accretion streams onto Classical T Tauri Stars: UV and X-ray emission lines
• Hydrodynamic Modeling of Accretion Impacts in Classical T Tauri Stars: Radiative Heating of the Pre-shock Plasma
• Molecules in the transition disk orbiting T Cha
• The accretion dynamics of EX Lupi in quiescence:The star, the spot, and the accretion column
• A Combined Spitzer and Herschel Infrared Study of Gas and Dust in the Circumbinary Disk Orbiting V4046 Sgr
• Sub-arcsec Observations of NGC 7538 IRS 1: Continuum Distribution and Dynamics of Molecular Gas
• Small-scale magnetic fields of the spectroscopic binary T Tauri stars V1878 Ori and V4046 Sir
• MN Lup: X-rays from a weakly accreting T Tauri star
• DN Tauri - coronal activity and accretion in a young low-mass CTTS
• X-ray variability of cool stars: Magnetic activity and accretion
• Pre main sequence: Accretion & Outflows
• High Energy Emission and its Variability in Young Stellar Objects
• The magnetosphere of the close accreting PMS binary V4046 Sgr
• Laboratory unravelling of matter accretion in young stars
• The magnetosphere of the close accreting PMS binary V4046 Sgr AB
• Nearby Young Stars and Young Moving Groups