We present an analysis of the Chandra High Energy Transmission Grating Spectrometer observation of the rapidly rotating (Prot=0.94days) post-T Tauri (~20 Myr old) star PZ Telescopii, in the Tucana association. Using two different methods, we have derived the coronal emission measure distribution EM(T) and chemical abundances. The EM(T) peaks at logT=6.9 and exhibits a significant emission measure at temperatures logT>7. The coronal abundances are generally ~0.5 times the solar photospheric values, which are presumed fairly representative of the composition of the underlying star. A minimum in abundance is seen at a first ionization potential (FIP) of 7-8 eV, with evidence for higher abundances at both lower and higher FIP, similar to patterns seen in other active stars. From an analysis of the He-like triplet of Mg XI, we have estimated electron densities of ~10^12-10^13 cm^-3. All the coronal properties found for PZ Tel are much more similar to those of AB Dor, which is slightly older than PZ Tel, than to those of the younger T Tauri star TW Hya. These results support earlier conclusions that the soft X-ray emission of TW Hya is likely dominated by accretion activity rather than by a magnetically heated corona. Our results also suggest that the coronae of pre-main-sequence stars rapidly become similar to those of older active main-sequence stars soon after the accretion stage has ended.

ARGIROFFI, C., DRAKE, J.J., MAGGIO, A., PERES, G., SCIORTINO, S., HARNDEN, F.R. (2004). High-Resolution X-Ray Spectroscopy of the Post-T Tauri Star PZ Telescopii. THE ASTROPHYSICAL JOURNAL, 609, 925-934 [10.1086/420692].

High-Resolution X-Ray Spectroscopy of the Post-T Tauri Star PZ Telescopii

ARGIROFFI, Costanza;PERES, Giovanni;
2004

Abstract

We present an analysis of the Chandra High Energy Transmission Grating Spectrometer observation of the rapidly rotating (Prot=0.94days) post-T Tauri (~20 Myr old) star PZ Telescopii, in the Tucana association. Using two different methods, we have derived the coronal emission measure distribution EM(T) and chemical abundances. The EM(T) peaks at logT=6.9 and exhibits a significant emission measure at temperatures logT>7. The coronal abundances are generally ~0.5 times the solar photospheric values, which are presumed fairly representative of the composition of the underlying star. A minimum in abundance is seen at a first ionization potential (FIP) of 7-8 eV, with evidence for higher abundances at both lower and higher FIP, similar to patterns seen in other active stars. From an analysis of the He-like triplet of Mg XI, we have estimated electron densities of ~10^12-10^13 cm^-3. All the coronal properties found for PZ Tel are much more similar to those of AB Dor, which is slightly older than PZ Tel, than to those of the younger T Tauri star TW Hya. These results support earlier conclusions that the soft X-ray emission of TW Hya is likely dominated by accretion activity rather than by a magnetically heated corona. Our results also suggest that the coronae of pre-main-sequence stars rapidly become similar to those of older active main-sequence stars soon after the accretion stage has ended.
Settore FIS/05 - Astronomia E Astrofisica
ARGIROFFI, C., DRAKE, J.J., MAGGIO, A., PERES, G., SCIORTINO, S., HARNDEN, F.R. (2004). High-Resolution X-Ray Spectroscopy of the Post-T Tauri Star PZ Telescopii. THE ASTROPHYSICAL JOURNAL, 609, 925-934 [10.1086/420692].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/33127
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