# 2007A&A...468..529G

 other querymodes : Identifierquery Coordinatequery Criteriaquery Referencequery Basicquery Scriptsubmission TAP Outputoptions Help

 Query : 2007A&A...468..529G

2007A&A...468..529G - Astronomy and Astrophysics, volume 468, 529-540 (2007/6-3)

X-rays from T Tauri: a test case for accreting T Tauri stars.

GUEDEL M., SKINNER S.L., MELNIKOV S.Y., AUDARD M., TELLESCHI A. and BRIGGS K.R.

Abstract (from CDS):

The generation of X-rays in accreting T Tauri stars (TTS) is thought to be predominantly due to energy dissipation in magnetic fields, but alternative X-ray generation mechanisms have been proposed, such as heating in accretion shocks near the stellar surface, or in shocks forming in jets. We test models and trends discussed in the literature using X-ray data from the classical TTS T Tau. High-resolution spectroscopy from the Reflection Grating Spectrometers on XMM-Newton is used to infer electron densities, element abundances and the thermal structure of the X-ray source. We also discuss the ultraviolet light curve obtained by the Optical Monitor, and complementary ground-based photometry. A high-resolution image from Chandra constrains contributions from the two companions of T Tau N. The X-ray grating spectrum is rich in emission lines, but shows an unusual mixture of features from very hot (≃30MK) and very cool (1-3MK) plasma, both emitted by similar amounts of emission measure. The cool plasma confirms the picture of a soft excess in the form of an enhanced Ovii/Oviii Lyα flux ratio, similar to that previously reported for other accreting TTS. Diagnostics from lines formed by this plasma indicate low electron densities (≲1010cm–3). The Ne/Fe abundance ratio is consistent with a trend in pre-main sequence stars in which this ratio depends on spectral type, but not on accretion. On the basis of line density diagnostics, we conclude that the density of the cool soft-excess'' plasma is orders of magnitude below that predicted for an accretion shock, assuming previously determined accretion rates of (3-6)x10–8M/yr. We argue that loading of magnetic field lines with infalling material suppresses the heating process in a part of the corona. We thus suggest that the X-ray production of T Tau is influenced by the accretion process although the X-rays may not form in the bulk of the accretion footpoints.

Journal keyword(s): stars: coronae - stars: formation - stars: pre-main sequence - X-rays: stars - stars: individual: T Tauri

Full paper

 Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* BP Tau Or* 04 19 15.8339827632 +29 06 26.926959492   13.13 12.12 11.89   K5/7Ve 632 0
2 IRAS 04187+1927 TT* 04 21 43.2345350808 +19 34 13.311438132       15.41   M2.4 47 0
3 V* T Tau TT* 04 21 59.4319873992 +19 32 06.432393336   11.22 10.12 9.80   K0IV/Ve 1364 1
4 2MASS J04220496+1934483 TT* 04 22 04.9620264720 +19 34 48.392208264           M3.5 24 0
5 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3926 0
6 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 1736 1
7 HD 98800 TT* 11 22 05.28975 -24 46 39.7571   10.20 9.28 9.26 7.386 K5V(e) 351 0
8 CD-33 7795 TT* 11 31 55.2608963280 -34 36 27.203892120   12.97 11.524 11.150 9.150 M2Ve 186 0
9 HD 319139 SB* 18 14 10.4818675368 -32 47 34.516836060   11.47 10.68   9.11 K5+K7 328 0

To bookmark this query, right click on this link: simbad:objects in 2007A&A...468..529G and select 'bookmark this link' or equivalent in the popup menu

2022.05.27-08:10:07