Why are accreting T Tauri stars observed to be less luminous in X-rays than non-accretors?
arXiv:0704.2958 · doi:10.1111/j.1745-3933.2007.00328.x
Abstract
Accreting T Tauri stars are observed to be less luminous in X-rays than non-accretors, an effect that has been detected in various star forming regions. To explain this we have combined, for the first time, a radiative transfer code with an accretion model that considers magnetic fields extrapolated from surface magnetograms obtained from Zeeman-Doppler imaging. Such fields consist of compact magnetic regions close to the stellar surface, with extended field lines interacting with the disc. We study the propagation of coronal X-rays through the magnetosphere and demonstrate that they are strongly absorbed by the dense gas in accretion columns. The reduction in the observed X-ray emission depends on the field geometry, which may explain why accreting T Tauri stars show a larger scatter in their observed X-ray luminosity compared to non-accreting stars.
arXiv comment5 pages, 2 figures (reduced quality). Accepted for publication in MNRAS Letters
References in corpus (21)
- Accretion Disks around Young Objects. I. The Detailed Vertical Structure
- The Origin of T Tauri X-ray Emission: New Insights from the Chandra Orion Ultradeep Project
- 2-D Radiative Transfer in Protostellar Envelopes: I. Effects of Geometry on Class I Sources
- Chandra Orion Ultradeep Project: Observations and Source Lists
- Bright X-ray flares in Orion young stars from COUP: evidence for star-disk magnetic fields?
- X-rays in the Orion Nebula Cluster: Constraints on the origins of magnetic activity in pre-main sequence stars
- X-ray emission from young stars in Taurus-Auriga-Perseus: Luminosity functions and the rotation-activity-age relation
- Chandra X-ray Observation of the Orion Nebula Cluster. II Relationship between X-ray activity indicators and stellar parameters
- The spin of accreting stars: dependence on magnetic coupling to the disc
- Infrared Signatures of Protoplanetary Disk Evolution
- X-ray emission from classical T Tauri stars: Accretion shocks and coronae?
- X-ray emission from T Tauri stars
- Mass Accretion onto T Tauri Stars
- X-ray Properties of Pre--Main-Sequence Stars in the Orion Nebula Cluster with Known Rotation Periods
- ACIS-I observations of NGC2264. Membership and X-ray properties of PMS stars
- Inferring X-ray coronal structures from Zeeman-Doppler images
- Chandra X-ray Observation of the Orion Nebula Cluster. I Detection, Identification and Determination of X-ray Luminosities
- Observational clues for a role of circumstellar accretion in PMS X-ray activity
- Emission-line profile modelling of structured T Tauri magnetospheres
- Rotationally Modulated X-ray Emission from T Tauri Stars
- CaII Infrared triplet line models in Classical T Tauri stars
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- Variable X-ray emission from the accretion shock in the Classical T Tauri Star V2129 Oph
- Radiative accretion shocks along nonuniform stellar magnetic fields in classical T Tauri stars
- Protoplanetary Disk Evolution around the Triggered Star Forming Region Cepheus B
- Physical Conditions of Accreting Gas in T Tauri Star Systems
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- X-ray variability of PMS stars - Toward an explanation of the different X-ray properties of CTTS and WTTS
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- X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae
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- A new view of the corona of classical T Tauri stars: Effects of flaring activity in circumstellar disks
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- Laboratory evidence for asymmetric accretion structure upon slanted matter impact in young stars
- Detection of a Cool, Accretion Shock-Generated X-ray Plasma in EX Lupi During the 2008 Optical Eruption
- Spatially-resolved Chandra Imaging Spectroscopy of the classical/weak-lined T Tauri system V710 Tau
- Variability of young stellar objects: accretion, disks, outflows and magnetic activity
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