@Article{DamineliFACDGHHJMMNRRSSW:2019:DiCiSt,
author = "Damineli, Augusto and Fernandez-Lajus, E. and Almeida, L. A. and
Corcoran, M. F. and Damineli, D. S. C. and Gull, T. R. and
Hamaguchi, K. and Hillier, D. J. and Jablonski, Francisco
Jos{\'e} and Madura, T. I. and Moffat, A. F. J. and Navarete,
Felipe and Richardson, Noel D. and Ruiz, G. F. and Salerno, N. E.
and Scalia, M. C. and Weigelt, Gerd",
affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidad Nacional
de La Plata} and {Universidade de S{\~a}o Paulo (USP)} and {NASA
Goddard Space Flight Center} and {University of Maryland} and
{NASA Goddard Space Flight Center} and {NASA Goddard Space Flight
Center} and {University of Pittsburgh} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {San Jose State University} and
{Universit{\'e} de Montr{\'e}al} and {Universidade de S{\~a}o
Paulo (USP)} and {The University of Toledo} and {Universidade de
S{\~a}o Paulo (USP)} and {Universidad Nacional de La Plata} and
{Universidad Nacional de La Plata} and {Max Planck Institute for
Radio Astronomy}",
title = "Distinguishing circumstellar from stellar photometric variability
in Eta Carinae",
journal = "Monthly Notices of the Royal Astronomical Society",
year = "2019",
volume = "484",
number = "1",
pages = "1325--1346",
month = "Mar.",
keywords = "binaries: general, stars: evolution, stars: individual (eta
Carinae), stars: winds, outflows, dust, extinction.",
abstract = "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
(Delta V similar to 0.6 mag) attributed to the wind-wind 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 2-3 and 8-10 yr and low amplitude, Delta 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 'shell ejections' 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 Delta V similar to 1
mag.",
doi = "10.1093/mnras/stz067",
url = "http://dx.doi.org/10.1093/mnras/stz067",
issn = "0035-8711 and 1365-2966",
language = "en",
targetfile = "damineli_distinguishing.pdf",
urlaccessdate = "27 abr. 2024"
}