2009ApJ...703.1224D


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.25CET06:59:46

2009ApJ...703.1224D - Astrophys. J., 703, 1224-1229 (2009/October-1)

An absence of X-ray accretion shock instability signatures in TW Hydrae.

DRAKE J.J., RATZLAFF P.W., LAMING J.M. and RAYMOND J.

Abstract (from CDS):

Gas accreting onto T Tauri stars should form shocks that are susceptible to the classical radiative shock instability. The instability should give rise to strong periodic modulation in the X-ray emission from the shock-heated plasma. Time series analysis of soft X-rays thought to arise predominantly in an accretion shock on the classical T Tauri star TW Hydrae reveals no periodic variations and a 99% confidence pulsed fraction limit of 5% over the frequency range 0.0001-6.81 Hz. We find no clear explanation for the absence of X-ray instability signatures, but suggest that existing one-dimensional models are too simple to explain the three-dimensional shock structure, or that preheating and deceleration of the accretion stream by the damping of magnetohydrodynamic waves excited either by the shock itself, or more deeply in the stellar envelope, could ameliorate the instability in the likely case of a sub-Alfvénic shock.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: formation - stars: individual: TW hydrae - X-rays: stars

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* EF Eri NL* 03 14 13.2527107604 -22 35 42.917018996   15.4 14.53 13.5   ~ 412 0
2 V* BP Tau Or* 04 19 15.8342975037 +29 06 26.929456808   13.13 12.12 11.89   K5/7Ve 606 0
3 V* VV Pup AM* 08 15 06.8010742098 -19 03 17.765651066     13.90     M7V 385 0
4 V* TW Hya TT* 11 01 51.9054298616 -34 42 17.031550898   11.94 10.50 10.626 9.18 K6Ve 1568 1
5 V* AN UMa CV* 11 04 25.6556953228 +45 03 13.941355292     14.90     ~ 246 0
6 CPD-68 1894 TT* 13 22 07.5420267499 -69 38 12.216304202   11.38 10.393   9.117 K1Ve 131 0
7 V* V834 Cen AM* 14 09 07.2853539143 -45 17 16.015131476   16.0       M6.5 301 0
8 V* MN Lup TT* 15 23 30.3994212749 -38 21 28.834461499     14.15     M0 23 0
9 V* RU Lup Or* 15 56 42.3109948086 -37 49 15.473469159 9.27 10.07 9.60     K7/M0e 393 0
10 EM* SR 9 Or* 16 27 40.2858402419 -24 22 04.132012501   12.91 11.533 11.11 10.00 K5e 255 0
11 HD 319139 BY* 18 14 10.4818974563 -32 47 34.516106830   11.47 10.68   9.11 K5+K7 297 0

    Equat.    Gal    SGal    Ecl

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2020.11.25-06:59:46

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