3 research outputs found
Fast Object Segmentation in Unconstrained Video
Interstellar matter and star formatio
Distinguishing circumstellar from stellar photometric variability in Eta Carinae
The interacting binary Eta Carinae remains one of the most enigmatic massive stars in our Galaxy despite over four centuries of observations. In this work, its light curve from the ultraviolet to the near-infrared is analysed using spatially resolved HST observations and intense monitoring at the La Plata Observatory, combined with previously published photometry. We have developed a method to separate the central stellar object in the ground-based images using HST photometry and applying it to the more numerous ground-based data, which supports the hypothesis that the central source is brightening faster than the almost-constant Homunculus. After detrending from long-term brightening, the light curve shows periodic orbital modulation (V ⌠0.6 mag) attributed to the windâwind collision cavity as it sweeps around the primary star and it shows variable projected area to our line-of-sight. Two quasi-periodic components with time-scales of 2â3 and 8â10 yr and low amplitude, V < 0.2 mag, are superimposed on the brightening light curve, being the only stellar component of variability found, which indicates minimal stellar instability. Moreover, the light-curve analysis shows no evidence of âshell ejectionsâ at periastron. We propose that the long-term brightening of the stellar core is due to the dissipation of a dusty clump in front of the central star, which works like a natural coronagraph. Thus, the central stars appear to be more stable than previously thought since the dominant variability originates from a changing circumstellar medium. We predict that the brightening phase, due mainly to dust dissipation, will be completed around 2032 ± 4 yr, when the star will be brighter than in the 1600s by up to V ⌠1 mag.Fil: Damineli, A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Almeida, L.A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. Universidade Federal do Rio Grande do Norte; BrasilFil: Corcoran, M.F.. National Aeronautics and Space Administration; Estados Unidos. The Catholic University of America; Estados UnidosFil: Damineli, D.S.C.. University of Maryland; Estados UnidosFil: Gull, T.R.. National Aeronautics and Space Administration; Estados UnidosFil: Hamaguchi, K. National Aeronautics and Space Administration; Estados Unidos. University of Maryland; Estados UnidosFil: Hillier, D.J.. University of Pittsburgh; Estados UnidosFil: Jablonski, F.J.. Centro de Previsao de Tempo e Estudos ClimĂĄticos. Instituto Nacional de Pesquisas Espaciais; BrasilFil: Madura, T.I.. San Jose State University; Estados UnidosFil: Moffat, A.F.J.. UniversitĂ© du QuĂ©bec a Montreal; CanadĂĄFil: Navarete, F.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Richardson, N.D.. University Of Toledo (utoledo); Estados UnidosFil: Ruiz, G.F.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Salerno, N.E.. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; ArgentinaFil: Scalia, MarĂa Cecilia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Weigelt, G.. Max Planck Institute For Radio Astronomy; Alemani