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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" (2012) Astrophysical Journal Letters. 760(2)
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Abstract:

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.

Registro:

Documento: Artículo
Título:X-ray determination of the variable rate of mass accretion onto TW hydrae
Autor:Brickhouse, N.S.; Cranmer, S.R.; Dupree, A.K.; Günther, H.M.; Luna, G.J.M.; Wolk, S.J.
Filiación:Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, United States
Instituto de Astronomia y Fisica Del Espacio (IAFE), Buenos Aires, Argentina
Palabras clave:accretion, accretion disks; stars: formation; stars: individual (TW Hydrae); techniques: spectroscopic; X-rays: stars
Año:2012
Volumen:760
Número:2
DOI: http://dx.doi.org/10.1088/2041-8205/760/2/L21
Título revista:Astrophysical Journal Letters
Título revista abreviado:Astrophys. J. Lett.
ISSN:20418205
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20418205_v760_n2_p_Brickhouse

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Citas:

---------- APA ----------
Brickhouse, N.S., Cranmer, S.R., Dupree, A.K., Günther, H.M., Luna, G.J.M. & Wolk, S.J. (2012) . X-ray determination of the variable rate of mass accretion onto TW hydrae. Astrophysical Journal Letters, 760(2).
http://dx.doi.org/10.1088/2041-8205/760/2/L21
---------- CHICAGO ----------
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" . Astrophysical Journal Letters 760, no. 2 (2012).
http://dx.doi.org/10.1088/2041-8205/760/2/L21
---------- MLA ----------
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" . Astrophysical Journal Letters, vol. 760, no. 2, 2012.
http://dx.doi.org/10.1088/2041-8205/760/2/L21
---------- VANCOUVER ----------
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. Astrophys. J. Lett. 2012;760(2).
http://dx.doi.org/10.1088/2041-8205/760/2/L21