Busca avançada
Ano de início
Entree
(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

He II lambda 4686 IN eta CARINAE: COLLAPSE OF THE WIND-WIND COLLISION REGION DURING PERIASTRON PASSAGE

Texto completo
Autor(es):
Mostrar menos -
Teodoro, M. [1] ; Damineli, A. [1] ; Arias, J. I. [2] ; de Araujo, F. X. [3] ; Barba, R. H. [4] ; Corcoran, M. F. [5, 6] ; Borges Fernandes, M. [3] ; Fernandez-Lajus, E. [7] ; Fraga, L. [8] ; Gamen, R. C. [7] ; Gonzalez, J. F. [4] ; Groh, J. H. [9] ; Marshall, J. L. [10] ; McGregor, P. J. [11] ; Morrell, N. [12] ; Nicholls, D. C. [11] ; Parkin, E. R. [11] ; Pereira, C. B. [3] ; Phillips, M. M. [12] ; Solivella, G. R. [7] ; Steiner, J. E. [1] ; Stritzinger, M. [13] ; Thompson, I. [14] ; Torres, C. A. O. [15] ; Torres, M. A. P. [16] ; Zevallos Herencia, M. I. [3]
Número total de Autores: 26
Afiliação do(s) autor(es):
Mostrar menos -
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[2] Univ La Serena, Dept Fis, La Serena - Chile
[3] Observ Nacl, BR-20921400 Rio De Janeiro - Brazil
[4] Consejo Nacl Invest Cient & Tecn, ICATE, San Juan - Argentina
[5] CRESST, Greenbelt, MD 20771 - USA
[6] NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 - USA
[7] Univ Nacl La Plata, Fac Ciencias Astron & Geofis, La Plata, BA - Argentina
[8] So Observ Astrophys Res, La Serena - Chile
[9] Max Planck Inst Radioastron, D-53121 Bonn - Germany
[10] Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 - USA
[11] RSAA, Mt Stromlo Observ, Weston, ACT 2611 - Australia
[12] Observ Carnegie Inst Washington, Las Campanas Observ, La Serena - Chile
[13] Stockholm Univ, Dept Astron, Oskar Klein Ctr, S-10691 Stockholm - Sweden
[14] Observ Carnegie Inst, Pasadena, CA 91101 - USA
[15] Lab Nacl Astrofis, BR-37504364 Bairro Das Nacoes, Itajuba - Brazil
[16] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 - USA
Número total de Afiliações: 16
Tipo de documento: Artigo Científico
Fonte: ASTROPHYSICAL JOURNAL; v. 746, n. 1 FEB 10 2012.
Citações Web of Science: 24
Resumo

The periodic spectroscopic events in eta Carinae are now well established and occur near the periastron passage of two massive stars in a very eccentric orbit. Several mechanisms have been proposed to explain the variations of different spectral features, such as an eclipse by the wind-wind collision (WWC) boundary, a shell ejection from the primary star or accretion of its wind onto the secondary. All of them have problems explaining all the observed phenomena. To better understand the nature of the cyclic events, we performed a dense monitoring of eta Carinae with five Southern telescopes during the 2009 low-excitation event, resulting in a set of data of unprecedented quality and sampling. The intrinsic luminosity of the He II lambda 4686 emission line (L similar to 310 L-circle dot) just before periastron reveals the presence of a very luminous transient source of extreme UV radiation emitted in the WWC region. Clumps in the primary's wind probably explain the flare-like behavior of both the X-ray and He II lambda 4686 light curves. After a short-lived minimum, He II lambda 4686 emission rises again to a new maximum, when X-rays are still absent or very weak. We interpret this as a collapse of the WWC onto the ``surface{''} of the secondary star, switching off the hard X-ray source and diminishing the WWC shock cone. The recovery from this state is controlled by the momentum balance between the secondary's wind and the clumps in the primary's wind. (AU)

Processo FAPESP: 09/08013-9 - Análise das variações de longo termo do espectro de Eta Carinae e criação de um pipeline de redução de dados para o espectrógrafo STELES
Beneficiário:Mairan Macedo Teodoro
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 05/00190-8 - Análise espectral das variações de longo termo do brilho de η Carinae
Beneficiário:Mairan Macedo Teodoro
Linha de fomento: Bolsas no Brasil - Doutorado