X-ray determination of the variable rate of mass accretion onto TW hydrae

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Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (N H) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star di...

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Detalles Bibliográficos
Autores principales:	Brickhouse, N.S., Cranmer, S.R., Dupree, A.K., Günther, H.M., Luna, G.J.M., Wolk, S.J.
Formato:	JOUR
Materias:	accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic X-rays: stars
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_20418205_v760_n2_p_Brickhouse
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_20418205_v760_n2_p_Brickhouse
record_format	dspace
spelling	todo:paper_20418205_v760_n2_p_Brickhouse2023-10-03T16:38:02Z X-ray determination of the variable rate of mass accretion onto TW hydrae Brickhouse, N.S. Cranmer, S.R. Dupree, A.K. Günther, H.M. Luna, G.J.M. Wolk, S.J. accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic X-rays: stars Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (N H) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star directly from measurements of the accreting material. The new method introduces the use of the absorption of Ne IX lines as a measure of the column density of the intervening, accreting material. On average, the derived mass accretion rate for TW Hya is 1.5 × 10 -9 M ⊙yr-1, for a stellar magnetic field strength of 600G and a filling factor of 3.5%. Three individual Chandra exposures show statistically significant differences in the Ne IX line ratios, indicating changes in N H, Te , and ne by factors of 0.28, 1.6, and 1.3, respectively. In exposures separated by 2.7days, the observations reported here suggest a five-fold reduction in the accretion rate. This powerful new technique promises to substantially improve our understanding of the accretion process in young stars. © 2012. The American Astronomical Society. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_20418205_v760_n2_p_Brickhouse
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic X-rays: stars
spellingShingle	accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic X-rays: stars Brickhouse, N.S. Cranmer, S.R. Dupree, A.K. Günther, H.M. Luna, G.J.M. Wolk, S.J. X-ray determination of the variable rate of mass accretion onto TW hydrae
topic_facet	accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic X-rays: stars
description	Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (N H) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star directly from measurements of the accreting material. The new method introduces the use of the absorption of Ne IX lines as a measure of the column density of the intervening, accreting material. On average, the derived mass accretion rate for TW Hya is 1.5 × 10 -9 M ⊙yr-1, for a stellar magnetic field strength of 600G and a filling factor of 3.5%. Three individual Chandra exposures show statistically significant differences in the Ne IX line ratios, indicating changes in N H, Te , and ne by factors of 0.28, 1.6, and 1.3, respectively. In exposures separated by 2.7days, the observations reported here suggest a five-fold reduction in the accretion rate. This powerful new technique promises to substantially improve our understanding of the accretion process in young stars. © 2012. The American Astronomical Society. All rights reserved.
format	JOUR
author	Brickhouse, N.S. Cranmer, S.R. Dupree, A.K. Günther, H.M. Luna, G.J.M. Wolk, S.J.
author_facet	Brickhouse, N.S. Cranmer, S.R. Dupree, A.K. Günther, H.M. Luna, G.J.M. Wolk, S.J.
author_sort	Brickhouse, N.S.
title	X-ray determination of the variable rate of mass accretion onto TW hydrae
title_short	X-ray determination of the variable rate of mass accretion onto TW hydrae
title_full	X-ray determination of the variable rate of mass accretion onto TW hydrae
title_fullStr	X-ray determination of the variable rate of mass accretion onto TW hydrae
title_full_unstemmed	X-ray determination of the variable rate of mass accretion onto TW hydrae
title_sort	x-ray determination of the variable rate of mass accretion onto tw hydrae
url	http://hdl.handle.net/20.500.12110/paper_20418205_v760_n2_p_Brickhouse
work_keys_str_mv	AT brickhousens xraydeterminationofthevariablerateofmassaccretionontotwhydrae AT cranmersr xraydeterminationofthevariablerateofmassaccretionontotwhydrae AT dupreeak xraydeterminationofthevariablerateofmassaccretionontotwhydrae AT guntherhm xraydeterminationofthevariablerateofmassaccretionontotwhydrae AT lunagjm xraydeterminationofthevariablerateofmassaccretionontotwhydrae AT wolksj xraydeterminationofthevariablerateofmassaccretionontotwhydrae
_version_	1807322126096531456

X-ray determination of the variable rate of mass accretion onto TW hydrae

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