A LIGHTHOUSE EFFECT IN ETA CARINAE

Journal Article · Mon Feb 20 04:00:00 EST 2012 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/746/2/L18· OSTI ID:22048049

Madura, Thomas I; Groh, Jose H ^[1]

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1. Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)

We present a new model for the behavior of scattered time-dependent, asymmetric near-UV emission from the nearby ejecta of {eta} Car. Using a three-dimensional (3D) hydrodynamical simulation of {eta} Car's binary colliding winds, we show that the 3D binary orientation derived by Madura et al. in 2012 is capable of explaining the asymmetric near-UV variability observed in the Hubble Space Telescope Advanced Camera for Surveys/High Resolution Camera F220W images of Smith et al.. Models assuming a binary orientation with i Almost-Equal-To 130 Degree-Sign -145 Degree-Sign , {omega} Almost-Equal-To 230 Degree-Sign -315 Degree-Sign , P.A.{sub z} Almost-Equal-To 302 Degree-Sign -327 Degree-Sign are consistent with the observed F220W near-UV images. We find that the hot binary companion does not significantly contribute to the near-UV excess observed in the F220W images. Rather, we suggest that a bore-hole effect and the reduction of Fe II optical depths inside the wind-wind collision cavity carved in the extended photosphere of the primary star lead to the time-dependent directional illumination of circumbinary material as the companion moves about in its highly elliptical orbit.

• OSTI ID: 22048049
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 746; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
ASYMMETRY
CAMERAS
COLLISIONS
COMPUTERIZED SIMULATION
EMISSION
HYDRODYNAMICS
IMAGES
ORBITS
ORIENTATION
PHOTOSPHERE
RESOLUTION
STARS
TELESCOPES
THREE-DIMENSIONAL CALCULATIONS
TIME DEPENDENCE