Navegar

Colección

Datos Estadísticas

Artículo

Dupree, A.K.; Brickhouse, N.S.; Cranmer, S.R.; Luna, G.J.M.; Schneider, E.E.; Bessell, M.S.; Bonanos, A.; Crause, L.A.; Lawson, W.A.; Mallik, S.V.; Schuler, S.C. "TW Hya: Spectral variability, X-rays, and accretion diagnostics" (2012) Astrophysical Journal. 750(1)
Estamos trabajando para incorporar este artículo al repositorio
Consulte el artículo en la página del editor
Consulte la política de Acceso Abierto del editor

Abstract:

The nearest accreting T Tauri star, TW Hya was intensively and continuously observed over ∼17days with spectroscopic and photometric measurements from four continents simultaneous with a long segmented exposure using the Chandra satellite. Contemporaneous optical photometry from WASP-S indicates a 4.74day period was present during this time. The absence of a similar periodicity in the Hα flux and the total X-ray flux which are dominated by accretion processes and the stellar corona, respectively, points to a different source of photometric variations. The Hα emission line appears intrinsically broad and symmetric, and both the profile and its variability suggest an origin in the post-shock cooling region. An accretion event, signaled by soft X-rays, is traced spectroscopically for the first time through the optical emission line profiles. After the accretion event, downflowing turbulent material observed in the Hα and Hβ lines is followed by He I (λ5876) broadening near the photosphere. Optical veiling resulting from the heated photosphere increases with a delay of ∼2hr after the X-ray accretion event. The response of the stellar coronal emission to an increase in the veiling follows ∼2.4hr later, giving direct evidence that the stellar corona is heated in part by accretion. Subsequently, the stellar wind becomes re-established. We suggest a model that incorporates the dynamics of this sequential series of events: an accretion shock, a cooling downflow in a supersonically turbulent region, followed by photospheric and later, coronal heating. This model naturally explains the presence of broad optical and ultraviolet lines, and affects the mass accretion rates determined from emission line profiles. © 2012. The American Astronomical Society. All rights reserved.

Registro:

Documento: Artículo
Título:TW Hya: Spectral variability, X-rays, and accretion diagnostics
Autor:Dupree, A.K.; Brickhouse, N.S.; Cranmer, S.R.; Luna, G.J.M.; Schneider, E.E.; Bessell, M.S.; Bonanos, A.; Crause, L.A.; Lawson, W.A.; Mallik, S.V.; Schuler, S.C.
Filiación:Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, United States
Australian National Observatory, Mount Stromlo Observatory, Canberra, ACT 2611, Australia
Institute of Astronomy and Astrophysics, National Observatory of Athens, 15236 Athens, Greece
South African Astronomical Observatory, Observatory 7935, P.O. Box 9, Cape Town, South Africa
School of Physical, Environmental and Math Sciences, University of New South Wales, Canberra, ACT 2600, Australia
Indian Institute of Astrophysics, Bangalore 560034, India
National Optical Astronomy Observatory, Tucson, AZ 85719, United States
Instituto de Astronomia y Fisica Del Espacio (IAFE), Buenos Aires, Argentina
Astronomy Department, University of Arizona, Tucson, AZ, United States
Palabras clave:accretion, accretion disks; stars: individual (TW Hydrae); stars: pre-main sequence; stars: variables: T Tauri, Herbig Ae/Be; stars: winds, outflows
Año:2012
Volumen:750
Número:1
DOI: http://dx.doi.org/10.1088/0004-637X/750/1/73
Título revista:Astrophysical Journal
Título revista abreviado:Astrophys. J.
ISSN:0004637X
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v750_n1_p_Dupree

Referencias:

  • Alencar, S.H.P., Batalha, C., (2002) ApJ, 571, p. 378
  • Ardila, D.R., Basri, G., Walter, F.M., Valenti, J.A., Johns-Krull, C.M., (2002) ApJ, 567, p. 1013
  • Batalha, C., Batalha, N.M., Alencar, S.H.P., Lopes, D.F., Duarte, E.S., (2002) ApJ, 580, p. 343
  • Bernstein, R., Shectman, S.A., Gunnels, S.M., Mochnacki, S., Athey, A.E., (2003) Proc. SPIE, 4841, p. 1694
  • Bertout, C., (1989) ARA&A, 27, p. 351
  • Brickhouse, N.S., Cranmer, S.R., Dupree, A.K., Luna, G.J.M., Wolk, S., (2010) ApJ, 710, p. 1835
  • Butters, O.W., West, R.G., Anderson, D.R., (2010) A&A, 520, p. 10
  • Costa, V.M., Lago, M.T.V.T., Norci, L., Meurs, E.J.A., (2000) A&A, 354, p. 621
  • Cranmer, S.R., (2008) ApJ, 689, p. 316
  • Cranmer, S.R., (2009) ApJ, 706, p. 824
  • Curran, R.L., Argiroffi, C., Sacco, G.G., (2011) A&A, 526, p. 104
  • Donati, J.-F., Gregory, S.G., Alencar, S.H.P., (2011) MNRAS, 417, p. 472
  • Dupree, A.K., Brickhouse, N.S., Smith, G.H., Strader, J., (2005) ApJ, 625, p. 131
  • Edwards, S., Fischer, W., Kwan, J., Hillenbrand, L., Dupree, A.K., (2003) ApJ, 599, p. 41
  • Günther, H.M., Schmitt, J.H.M.M., (2008) A&A, 481, p. 735
  • Hartigan, P., Hartmann, L., Kenyon, S., Hewett, R., Stauffer, J., (1989) ApJS, 70, p. 899
  • Hartmann, L., Hewett, R., Calvet, N., (1994) ApJ, 426, p. 669
  • Herczeg, G.J., Linsky, J.L., Valenti, J.A., Johns-Krull, C.M., Wood, B.E., (2002) ApJ, 572, p. 310
  • Horne, J.H., Baliunas, S.L., (1986) ApJ, 302, p. 757
  • Huélamo, N., Figueira, P., Bonfils, X., (2008) A&A, 489, p. 9
  • Hummer, D.G., Rybicki, G.B., (1968) ApJ, 153, p. 107
  • Kastner, J.H., Huenemoerder, D.P., Schulz, N.S., Canizares, C.R., Weintraub, D.A., (2002) ApJ, 567, p. 434
  • Kastner, J.H., Huenemoerder, D.P., Schulz, N.S., Weintraub, D.A., (1999) ApJ, 525, p. 837
  • Koen, C., Eyer, L., (2002) MNRAS, 331, p. 45
  • Krist, J.E., Stapelfeldt, K.R., Ménard, F., Padgett, D.L., Burrows, C.J., (2000) ApJ, 538, p. 793
  • Kurosawa, R., Romanova, M.M., Harries, T.J., (2011) MNRAS, 416, p. 2623
  • Lamzin, S.A., Romanova, M.M., Kravtsova, A.S., (2007) Symp. 243, Star-Disk Interaction in Young Stars, p. 115
  • Lawson, W.A., Crause, L.A., (2005) MNRAS, 357, p. 1399
  • Lawson, W.A., Crause, L.A., Mamajek, E.E., Feigelson, E.D., (2001) MNRAS, 321, p. 57
  • Mallik, S.V., Brickhouse, N.S., Dupree, A.K., (2010) Recent Advances in Spectroscopy Theoretical, Astrophysical, and Experimental Perspectives, p. 193
  • Mekkaden, M.V., (1998) A&A, 340, p. 135
  • Muzerolle, J., Calvet, N., Bricẽo, C., Hartmann, L., Hillenbrand, L., (2000) ApJ, 535, p. 47
  • Muzerolle, J., Calvet, N., Hartmann, L., (1998) ApJ, 492, p. 743
  • Muzerolle, J., Calvet, N., Hartmann, L., (2001) ApJ, 550, p. 944
  • Muzerolle, J., Hartmann, L., Calvet, N., (1998) AJ, 116, p. 455
  • Natta, A., Testi, L., Muzerolle, J., (2004) A&A, 424, p. 603
  • Pojmanski, G., (2002) Acta Astron., 52, p. 397
  • Qi, C., Ho, P.T.P., Wilner, D.J., (2004) ApJ, 616, p. 11
  • Romanova, M.M., Ustyugova, G.V., Koldoba, A.V., Lovelace, R.V.E., (2004) ApJ, 610, p. 920
  • Rothman, L.S., Gordon, I.E., Barbe, A., (2009) J. Quant. Spectrosc. Radiat. Transfer, 110, p. 533
  • Rucinski, S.M., Krautter, J., (1983) A&A, 121, p. 217
  • Rucinski, S.M., Matthews, J.M., Kuschnig, R., (2008) MNRAS, 391, p. 1913
  • Sacco, G.G., Orlando, S., Argiroffi, C., (2010) A&A, 522, p. 55
  • Scargle, J.D., (1982) ApJ, 263, p. 835
  • Siwak, M., Rucinski, S.M., Matthews, J.M., (2011) MNRAS, 410, p. 2725
  • Stassun, K.G., Van Den Berg, M., Feigelson, E., (2007) ApJ, 660, p. 704
  • Stassun, K.G., Van Den Berg, M., Feigelson, E., Flaccomio, E., (2006) ApJ, 649, p. 914
  • Vacca, W.D., Sandell, G., (2011) ApJ, 732, p. 8
  • White, R.J., Basri, G., (2003) ApJ, 582, p. 1109
  • Wichmann, R., Bastian, U., Krautter, J., Jankovics, I., Rucinski, S.M., (1998) MNRAS, 301, pp. 39L
  • Yang, H., Johns-Krull, C.M., Valenti, J.A., (2007) AJ, 133, p. 73

Citas:

---------- APA ----------
Dupree, A.K., Brickhouse, N.S., Cranmer, S.R., Luna, G.J.M., Schneider, E.E., Bessell, M.S., Bonanos, A.,..., Schuler, S.C. (2012) . TW Hya: Spectral variability, X-rays, and accretion diagnostics. Astrophysical Journal, 750(1).
http://dx.doi.org/10.1088/0004-637X/750/1/73
---------- CHICAGO ----------
Dupree, A.K., Brickhouse, N.S., Cranmer, S.R., Luna, G.J.M., Schneider, E.E., Bessell, M.S., et al. "TW Hya: Spectral variability, X-rays, and accretion diagnostics" . Astrophysical Journal 750, no. 1 (2012).
http://dx.doi.org/10.1088/0004-637X/750/1/73
---------- MLA ----------
Dupree, A.K., Brickhouse, N.S., Cranmer, S.R., Luna, G.J.M., Schneider, E.E., Bessell, M.S., et al. "TW Hya: Spectral variability, X-rays, and accretion diagnostics" . Astrophysical Journal, vol. 750, no. 1, 2012.
http://dx.doi.org/10.1088/0004-637X/750/1/73
---------- VANCOUVER ----------
Dupree, A.K., Brickhouse, N.S., Cranmer, S.R., Luna, G.J.M., Schneider, E.E., Bessell, M.S., et al. TW Hya: Spectral variability, X-rays, and accretion diagnostics. Astrophys. J. 2012;750(1).
http://dx.doi.org/10.1088/0004-637X/750/1/73