@Article{TeodoroDHRMSRGMPWCPFGHHNAJLLPBCCHGHW:2016:COOREL,
               author = "Teodoro, M. and Damineli, A. and Heathcote, B. and Richardson, N. 
                         D. and Moffat, A. F. J. and St-Jean, L. and Russell, C. and Gull, 
                         T. R. and Madura, T. I. and Pollard, K. R. and Walter, F. and 
                         Coimbra, A. and Prates, R. and Fern{\'a}ndez-Lajus, E. and Gamen, 
                         R. C. and Hickel, G. and Henrique, W. and Navarete, F. and 
                         Andrade, T. and Jablonski, Francisco Jos{\'e} and Luckas, P. and 
                         Locke, M. and Powles, J. and Bohlsen, T. and Chini, R. and 
                         Corcoran, M. F. and Hamaguchi, K. and Groh, J. H. and Hillier, D. 
                         J. and Weigelt, G.",
          affiliation = "{NASA Goddard Space Flight Center} and {Universidade de S{\~a}o 
                         Paulo (USP)} and {SASER Team} and {Universit{\'e} de 
                         Montr{\'e}al} and {Universit{\'e} de Montr{\'e}al} and 
                         {Universit{\'e} de Montr{\'e}al} and {NASA Goddard Space Flight 
                         Center} and {NASA Goddard Space Flight Center} and {NASA Goddard 
                         Space Flight Center} and {University of Canterbury} and {Stony 
                         Brook University} and {Laborat{\'o}rio Nacional de Astrofica} and 
                         {Laborat{\'o}rio Nacional de Astrofica} and {Universidad Nacional 
                         de la Plata} and {Universidad Nacional de la Plata} and 
                         {Universidade Federal de Itajub{\'a} (UNIFEI)} and {Universidade 
                         Federal de Itajub{\'a} (UNIFEI)} and {Universidade de S{\~a}o 
                         Paulo (USP)} and {Universidade de S{\~a}o Paulo (USP)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {SASER 
                         Team} and {SASER Team} and {SASER Team} and {SASER Team} and 
                         {Ruhr-Universitat Bochum} and {NASA Goddard Space Flight Center} 
                         and {NASA Goddard Space Flight Center} and {Geneva Observatory} 
                         and {University of Pittsburgh} and {Max-Planck-Institut f{\"u}r 
                         Radioastronomie}",
                title = "He II \λ4686 EMISSION from the MASSIVE BINARY SYSTEM in 
                         \η CAR: CONSTRAINTS to the ORBITAL ELEMENTS and the NATURE 
                         of the PERIODIC MINIMA",
              journal = "Astrophysical Journal",
                 year = "2016",
               volume = "819",
               number = "2",
                pages = "131",
                month = "Mar.",
             keywords = "binaries: general, circumstellar matter, stars: individual 
                         (\ν,,Carinae), stars: massive.",
             abstract = "Eta Carinae (\η Car) is an extremely massive binary system 
                         in which rapid spectrum variations occur near periastron. Most 
                         notably, near periastron the He ii \λ4686 line increases 
                         rapidly in strength, drops to a minimum value, then increases 
                         briefly before fading away. To understand this behavior, we 
                         conducted an intense spectroscopic monitoring of the He ii 
                         \λ4686 emission line across the 2014.6 periastron passage 
                         using ground- and space-based telescopes. Comparison with previous 
                         data confirmed the overall repeatability of the line equivalent 
                         width (EW), radial velocities, and the timing of the minimum, 
                         though the strongest peak was systematically larger in 2014 than 
                         in 2009 by 26%. The EW variations, combined with other 
                         measurements, yield an orbital period of 2022.7 ±0.3 days. The 
                         observed variability of the EW was reproduced by a model in which 
                         the line flux primarily arises at the apex of the wind-wind 
                         collision and scales inversely with the square of the stellar 
                         separation, if we account for the excess emission as the companion 
                         star plunges into the hot inner layers of the primary's 
                         atmosphere, and including absorption from the disturbed primary 
                         wind between the source and the observer. This model constrains 
                         the orbital inclination to 135°-153°, and the longitude of 
                         periastron to 234°-252°. It also suggests that periastron passage 
                         occurred on days). Our model also reproduced EW variations from a 
                         polar view of the primary star as determined from the observed He 
                         ii \λ4686 emission scattered off the Homunculus nebula.",
                  doi = "10.3847/0004-637X/819/2/131",
                  url = "http://dx.doi.org/10.3847/0004-637X/819/2/131",
                 issn = "0004-637X and 1538-4357",
             language = "en",
           targetfile = "Teodoro_he II.pdf",
        urlaccessdate = "27 abr. 2024"
}