• Maggio, Antonio
• Neuhäuser, R.
• Peres, G.
• Argiroffi, C.
• Stelzer, B.

Abstract

We present results of X-ray spectroscopy for <ASTROBJ>TWA 5</ASTROBJ>, a member of the young TW Hydrae association, observed with XMM-Newton. <ASTROBJ>TWA 5</ASTROBJ> is a multiple system which shows Hα emission, a signature typical of classical T Tauri stars, but no infrared excess. From this analysis of the RGS and EPIC spectra, we have derived the emission measure distribution vs. temperature of the X-ray emitting plasma, its abundances, and the electron density. The characteristic temperature and density of the plasma suggest a corona similar to that of weak-line T Tauri stars and active late-type main sequence stars. <ASTROBJ>TWA 5</ASTROBJ> also shows low iron abundance (~0.1 times the solar photospheric one) and a pattern of increasing abundances for elements with increasing first ionization potential reminiscent of the inverse FIP effect observed in highly active stars. The especially high ratio Ne/Fẽ10 is similar to that of the classical T Tauri star <ASTROBJ>TW Hya</ASTROBJ>, where the accreting material has been held responsible for the X-ray emission. We discuss the possible role of an accretion process in this scenario. Since all T Tauri stars in the TW Hydrae association studied so far have very high Ne/Fe ratios, we also propose that environmental conditions may cause this effect.

Topics

• density
• impedance spectroscopy
• iron
• X-ray spectroscopy