2010A&A...518A..54G


Query : 2010A&A...518A..54G

2010A&A...518A..54G - Astronomy and Astrophysics, volume 518, A54-54 (2010/7-2)

The absence of sub-minute periodicity in classical T Tauri stars.

GUENTHER H.M., LEWANDOWSKA N., HUNDERTMARK M.P.G., STEINLE H., SCHMITT J.H.M.M., BUCKLEY D., CRAWFORD S., O'DONOGHUE D. and VAISANEN P.

Abstract (from CDS):

Classical T Tauri stars (CTTS) are young, late-type objects, that still accrete matter from a circumstellar disk. Analytical treatments and numerical simulations predict instabilities of the accretion shock on the stellar surface. We search for variability on timescales below a few minutes in the CTTS TW Hya and AA Tau.TW Hya was observed with SALTICAM on the Southern African Large Telescope (SALT) in narrow-band filters around the Balmer jump. The observations were performed in slit mode, which provides a time resolution of about 0.1 s. For AA Tau we obtained observations with OPTIMA, a single photon-counting device with even better time resolution.Small-scale variability typically lasts a few seconds, however, no significant periodicity is detected. We place a 99% confidence upper limit on the pulsed fraction of the lightcurves. The relative amplitude is below 0.001 for TW Hya in the frequency range 0.02-3Hz in the 340nm filter and 0.1-3Hz in the 380nm filter. The corresponding value for AA Tau is an amplitude of 0.005 for 0.02-50Hz. The relevant timescales indicate that shock instabilites should not be seen directly in our optical and UV observations, but the predicted oscialltions would induce observable variations in the reddening. We discuss how the magnetic field could stabilise the accretion shock.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: individual: TW Hya - stars: individual: AA Tau - stars: oscillations - stars: variables: T Tauri, Ae/Be Herbig

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 V* AA Tau Or* 04 34 55.4201902392 +24 28 53.033624580 13.14 13.34 12.20 12.03   K5Ve 698 0
2 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 1787 1

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2023.01.30-21:57:56

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