Millimeter-wave emission during the 2003 low excitation phase of η Carinae

被引:30
作者
Abraham, Z
Falceta-Gonçalves, D
Dominici, TP
Nyman, LÅ
Durouchoux, P
McAuliffe, F
Caproni, A
Jatenco-Pereira, V
机构
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo, Brazil
[2] European So Observ, Santiago 19, Chile
[3] Onsala Space Observ, S-43992 Onsala, Sweden
[4] CEA Saclay, CNRS, URA 2052, Serv Astrophys, F-91191 Gif Sur Yvette, France
来源
ASTRONOMY & ASTROPHYSICS | 2005年 / 437卷 / 03期
关键词
stars : individual :eta Carinae; stars : binaries : general; stars : circumstellar matter; stars; winds; outflows; radio continuum : general;
D O I
10.1051/0004-6361:20041604
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
In this paper we present observations of eta Carinae in the 1.3 mm and 7 mm radio continuum, during the 2003.5 low excitation phase. The expected minimum in the light curves was confirmed at both wavelengths and was probably due to a decrease in the number of UV photons available to ionize the gas surrounding the binary system. At 7 mm a very well defined peak was superimposed on the declining flux density. It presented maximum amplitude in 29 June 2003 and lasted for about 10 days. We show that its origin can be free-free emission from the gas at the shock formed by wind-wind collision, which is also responsible for the observed X-ray emission. Even though the shock strength is strongly enhanced as the two stars in the binary system approach each other, during periastron passage the X-ray emission is strongly absorbed and the 7 mm observations represent the only direct evidence of this event.
引用
收藏
页码:977 / 981
页数:5
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