2006A&A...449..737R


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.21CEST04:30:30

2006A&A...449..737R - Astronomy and Astrophysics, volume 449, 737-747 (2006/4-2)

XMM-Newton X-ray spectroscopy of classical T Tauri stars.

ROBRADE J. and SCHMITT J.H.M.M.

Abstract (from CDS):

We present results from a comparative study of XMM-Newton observations of four classical T Tauri stars (CTTS), namely BP Tau, CR Cha, SU Aur and TW Hya. In these objects coronal, i.e. magnetic, activity and as recently shown, magnetically funneled accretion are the processes likely to be responsible for the generation of X-ray emission. Variable X-ray emission with luminosities in the order of 1030erg/s is observed for all targets. We investigate light curves as well as medium and high-resolution X-ray spectra to determine the plasma properties of the sample CTTS and to study the origin of their X-ray emission and its variability. The emission measure distributions and observed temperatures differ significantly and the targets are dominated either by plasma at high densities as produced by accretion shocks or by predominantly hotter plasma of coronal origin. Likewise the variability of the X-ray luminosity is found to be generated by both mechanisms. Cool plasma at high densities is found in all stars with detected OVII triplet emission, prevented only for SU Aur due to strong absorption. A general trend is present in the abundance pattern, with neon being at solar value or enhanced while oxygen, iron and most other metals are depleted, pointing to the presence of the inverse FIP effect in active coronae and possibly grain formation in evolved disks. We find that both accretion shocks and coronal activity contribute to the observed X-ray emission of the targets. While coronal activity is the dominant source of X-ray activity in the majority of the CTTS, the fraction for each process differs significantly between the individual objects.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: coronae - stars: late-type - stars: pre-main sequence - X-rays: stars

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 V* BP Tau Or* 04 19 15.8342975037 +29 06 26.929456808   13.13 12.12 11.89   K5/7Ve 603 0
2 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1226 0
3 V* SU Aur Or* 04 55 59.3861369488 +30 34 01.499800471   10.33 9.30 9.17   G2IIIne 537 0
4 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2012 1
5 Hen 3-545 Or* 10 59 06.9712894449 -77 01 40.309036535   12.91 11.136   9.596 K4Ve 190 0
6 V* TW Hya TT* 11 01 51.9054298616 -34 42 17.031550898   11.94 10.50 10.626 9.18 K6Ve 1553 1
7 NAME Cha I MoC 11 06 48 -77 18.0           ~ 985 1
8 CD-33 7795 TT* 11 31 55.2603055856 -34 36 27.214242128   12.97 11.524 11.150 9.150 M2Ve 176 0

    Equat.    Gal    SGal    Ecl

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2020.10.21-04:30:30

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