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New view of the corona of classical T Tauri stars: Effects of flaring activity in circumstellar disks
- Source :
- Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 624, pp.A50. ⟨10.1051/0004-6361/201834342⟩
- Publication Year :
- 2019
-
Abstract
- Classical T Tauri stars (CTTSs) are young low-mass stellar objects accreting mass from their circumstellar disks. They are characterized by high levels of coronal activity as revealed by X-ray observations. This activity may affect the disk stability and the circumstellar environment. Here we investigate if an intense coronal activity due to flares occurring close to the accretion disk may perturb the inner disk stability, disrupt the inner part of the disk and, possibly, trigger accretion phenomena with rates comparable with those observed. We model a magnetized protostar surrounded by an accretion disk through 3D magnetohydrodinamic simulations. We explore cases characterized by a dipole plus an octupole stellar magnetic field configuration and different density of the disk or by different levels of flaring activity. As a result of the simulated intense flaring activity, we observe the formation of several loops that link the star to the disk; all these loops build up a hot extended corona with an X-ray luminosity comparable with typical values observed in CTTSs. The intense flaring activity close to the disk can strongly perturb the disk stability. The flares trigger overpressure waves which travel through the disk and modify its configuration. Accretion funnels may be triggered by the flaring activity, thus contributing to the mass accretion rate of the star. Accretion rates synthesized from the simulations are in a range between 10^-10 and 10^-9M_sun yr^-1 The accretion columns can be perturbed by the flares and they can interact with each other, possibly merging together in larger streams. As a result, the accretion pattern can be rather complex: the streams are highly inhomogeneous, with a complex density structure, and clumped<br />Comment: 12 pages, 9 figures
- Subjects :
- Young stellar object
Stars: flare
Astrophysics::High Energy Astrophysical Phenomena
FOS: Physical sciences
X-rays: stars
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
accretion, accretion disk
01 natural sciences
magnetohydrodynamics (MHD)
Settore FIS/05 - Astronomia E Astrofisica
accretion
0103 physical sciences
Radiative transfer
Protostar
Astrophysics::Solar and Stellar Astrophysics
Stars: coronae
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Astrophysics::Galaxy Astrophysics
Physics
010308 nuclear & particles physics
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
accretion disks
Stellar magnetic field
Astronomy and Astrophysics
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
Corona
Accretion (astrophysics)
T Tauri star
Astrophysics - Solar and Stellar Astrophysics
Heat flux
13. Climate action
Space and Planetary Science
Stars: pre-main sequence
Astrophysics::Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00046361
- Database :
- OpenAIRE
- Journal :
- Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 624, pp.A50. ⟨10.1051/0004-6361/201834342⟩
- Accession number :
- edsair.doi.dedup.....e450fb8662f6b0151797b978eec35a74