Eta Carinae: an evolving view of the central binary, its interacting winds and its foreground ejecta

Abstract

FUV spectra of Eta Car, recorded across two decades with HST/STIS, document multiple changes in resonant lines caused by dissipating extinction in our line of sight. The FUV flux has increased nearly ten-fold which has led to increased ionization of the multiple shells within the Homunculus and photo-destruction of molecular hydrogen. Comparison of observed resonant line profiles with CMFGEN model profiles allows separation of wind-wind collision and shell absorptions from the primary wind, P Cygni profiles.The dissipating occulter preferentially obscured the central binary and interacting winds relative to the very extended primary wind. We are now able to monitor changes in the colliding winds with orbital phase. High velocity transient absorptions occurred across the most recent periastron passage, indicating acceleration of the primary wind by the secondary wind which leads to a downstream, high velocity bowshock that is newly generated every orbital period. There is no evidence of changes in the properties of the binary winds.

arXiv comment36 pages, 22 figures, accepted Astrophysical Journal

References in corpus (32)

• In Hot Pursuit of the Hidden Companion of Eta Carinae: An X-ray Determination of the Wind Parameters
• A Revised Historical Light Curve of Eta Carinae and the Timing of Close Periastron Encounters
• High-excitation emission lines near eta Carinae, and its likely companion star
• The UV Scattering Halo of the Central Source Associated with Eta Carinae
• The Binarity of Eta Carinae Revealed from Photoionization Modeling of the Spectral Variability of the Weigelt Blobs B and D
• Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission
• Constraints on decreases in Eta Carinae's mass loss from 3D hydrodynamic simulations of its binary colliding winds
• Eta Carinae across the 2003.5 minimum: Spectroscopic Evidence for Massive Binary Interactions
• X-ray Spectral Variation of Eta Carinae through the 2003 X-ray Minimum
• A multispectral view of the periodic events in eta Carinae
• On the influence of the companion star in Eta Carinae: 2D radiative transfer modeling of the ultraviolet and optical spectra
• A Clumping Independent Diagnostic of Stellar Mass-loss Rates: Rapid Clump Destruction in Adiabatic Colliding Winds
• He II $\lambda$4686 emission from the massive binary system in $\eta$ Car: constraints to the orbital elements and the nature of the periodic minima
• Detection of a Hot Binary Companion of $\eta$ Carinae
• $\eta$ Carinae's Dusty Homunculus Nebula from Near-Infrared to Submillimeter Wavelengths: Mass, Composition, and Evidence for Fading Opacity
• Ancient eruptions of Eta Carinae: A tale written in proper motions
• The Absorption Spectrum of High-Density Stellar Ejecta in the Line-of-Sight to Eta Carinae
• Detection of high-velocity material from the wind-wind collision zone of Eta Carinae across the 2009.0 periastron passage
• Secular Changes in Eta Carinae's Wind 1998-2011
• The three-dimensional structure of the Eta Carinae Homunculus
• Astrophysical Lasers Operating in optical Fe II Lines Lines in Stellar Ejecta of Eta Carinae
• Eta Carinae's 2014.6 Spectroscopic Event: Clues to the Long-term Recovery from its Great Eruption
• The fossil wind structures of Eta Carinae: changes across on 5.54-year cycle
• 3D radiative transfer simulations of Eta Carinae's inner colliding winds - I. Ionization structure of helium at apastron
• A Lighthouse Effect in Eta Carinae
• A companion as the cause of latitude-dependent effects in the wind of Eta Carinae
• Distinguishing Circumstellar from Stellar Photometric Variability in Eta Carinae
• To $v_{\infty }$ and beyond! The He I absorption variability across the 2014.6 periastron passage of $\eta$ Carinae
• 3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae's Inner Colliding Winds
• Time variations of the narrow FeII and HI spectral emission lines from the close vicinity of Eta Carinae during the spectral event of 2003
• Eta Carinae's Declining Outflow Seen in the UV, 2002-2015
• Spectroscopic Signatures of the Vanishing Natural Coronagraph of eta Carinae