He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage
The periodic spectroscopic events in η 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...
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| Autores principales: | , , , , , , , , , , , , , , , , , , , , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2012
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/84779 |
| Aporte de: |
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I19-R120-10915-84779 |
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| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas line: profiles stars: early-type stars: individual (eta Carinae) stars: massive |
| spellingShingle |
Ciencias Astronómicas line: profiles stars: early-type stars: individual (eta Carinae) stars: massive Teodoro, M. Damineli, A. Arias, Julia Inés Barbá, Rodolfo Héctor Corcoran, M. F. Borges Fernandes, M. Fernández Lajús, Eduardo Fraga, L. Gamen, Roberto Claudio González, J. F. Groh, J. H. Marshall, J. L. McGregor, P. J. Morrell, Nidia Irene Nicholls, D. C. Parkin, E. R. Pereira, C. B. Phillips, M. M. Solivella, Gladys Rebeca Steiner, J. E. Stritzinger, M. Thompson, I. Torres, C. A. O. Torres, M. A. P. Zevallos Herencia, M. I. He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| topic_facet |
Ciencias Astronómicas line: profiles stars: early-type stars: individual (eta Carinae) stars: massive |
| description |
The periodic spectroscopic events in η 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 η 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 λ4686 emission line (L 310 L) 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 λ4686 light curves. After a short-lived minimum, He II λ4686 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. |
| format |
Articulo Articulo |
| author |
Teodoro, M. Damineli, A. Arias, Julia Inés Barbá, Rodolfo Héctor Corcoran, M. F. Borges Fernandes, M. Fernández Lajús, Eduardo Fraga, L. Gamen, Roberto Claudio González, J. F. Groh, J. H. Marshall, J. L. McGregor, P. J. Morrell, Nidia Irene Nicholls, D. C. Parkin, E. R. Pereira, C. B. Phillips, M. M. Solivella, Gladys Rebeca Steiner, J. E. Stritzinger, M. Thompson, I. Torres, C. A. O. Torres, M. A. P. Zevallos Herencia, M. I. |
| author_facet |
Teodoro, M. Damineli, A. Arias, Julia Inés Barbá, Rodolfo Héctor Corcoran, M. F. Borges Fernandes, M. Fernández Lajús, Eduardo Fraga, L. Gamen, Roberto Claudio González, J. F. Groh, J. H. Marshall, J. L. McGregor, P. J. Morrell, Nidia Irene Nicholls, D. C. Parkin, E. R. Pereira, C. B. Phillips, M. M. Solivella, Gladys Rebeca Steiner, J. E. Stritzinger, M. Thompson, I. Torres, C. A. O. Torres, M. A. P. Zevallos Herencia, M. I. |
| author_sort |
Teodoro, M. |
| title |
He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| title_short |
He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| title_full |
He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| title_fullStr |
He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| title_full_unstemmed |
He II λ4686 in η Carinae: Collapse of the wind-wind collision region during periastron passage |
| title_sort |
he ii λ4686 in η carinae: collapse of the wind-wind collision region during periastron passage |
| publishDate |
2012 |
| url |
http://sedici.unlp.edu.ar/handle/10915/84779 |
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