A moderately precise dynamical age for the Homunculus of Eta Carinae based on 13 years of HST imaging

Abstract

The HST archive contains a large collection of images of eta Carinae, and this paper analyzes those most suitable for measuring its expanding Homunculus Nebula. Multiple intensity tracings through the Homunculus reveal the fractional increase in the overall size of the nebula; this avoids registration uncertainty, mitigates brightness fluctuations, and is independent of previous methods. Combining a 13-yr baseline of Wide Field Planetary Camera 2 (WFPC2) images in the F631N filter, with a 4-yr baseline of Advanced Camera for Surveys/High Resolution Channel (ACS/HRC) images in the F550M filter, yields an ejection date (assuming linear motion) of 1847.1 ($\pm$0.8 yr). This result improves the precision, but is in excellent agreement with the previous study by Morse et al.\ (2001) that used a shorter time baseline and a different analysis method. This more precise date is inconsistent with ejection during a periastron passage of the eccentric binary. Ejection occured well into the main plateau of the Great Eruption, and not during the brief peaks in 1843 and 1838. The age uncertainty is dominated by a real spread in ages of various knots, and by some irregular brightness fluctuations. Several knots appear to have been ejected decades before or after the mean date, implying a complicated history of mass-loss episodes outside the main bright phase of the eruption. The extended history of mass ejection may have been largely erased by the passage of a shock through clumpy ejecta, as most material was swept into a thin shell with nearly uniform apparent age.

arXiv comment11 pages, 4 figs. Please see published MNRAS version for proper formating, readable figures, and online movie

References in corpus (54)

• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
• On the role of continuum-driven eruptions in the evolution of very massive stars and Population III stars
• Luminous Blue Variable eruptions and related transients: Diversity of progenitors and outburst properties
• The Structure of the Homunculus: I. Shape and Latitude Dependence from H2 and [Fe II] Velocity Maps of Eta Carinae
• A Porosity-Length Formalism for Photon-Tiring-Limited Mass Loss from Stars Above the Eddington Limit
• In Hot Pursuit of the Hidden Companion of Eta Carinae: An X-ray Determination of the Wind Parameters
• Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey
• Tycho Brahe's 1572 supernova as a standard type Ia explosion revealed from its light echo spectrum
• Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)
• Echoes from Ancient Supernovae in the Large Magellanic Cloud
• Super-Eddington Stellar Winds Driven by Near-Surface Energy Deposition
• Direct Confirmation of the Asymmetry of the Cas A Supernova with Light Echoes
• A Revised Historical Light Curve of Eta Carinae and the Timing of Close Periastron Encounters
• Spiralling out of control: 3D hydrodynamical modelling of the colliding winds in $\eta$Carinae
• Dissecting the Homunculus nebula around Eta Carinae with spatially resolved near-infrared spectroscopy
• A Blast Wave from the 1843 Eruption of Eta Carinae
• Massive-Star Mergers and the Recent Transient in NGC4490: A More Massive Cousin of V838 Mon and V1309 Sco
• The Bubble-like Interior of the Core-Collapse Supernova Remnant Cassiopeia A
• Giant Outbursts of Luminous Blue Variables and the Formation of the Homunculus Nebula Around eta Carinae
• The 2003 Shell Event in eta Carinae
• Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission
• Light echoes reveal an unexpectedly cool Eta Carinae during its 19th-century Great Eruption
• Explosions Triggered by Violent Binary-Star Collisions: Application to Eta Carinae and other Eruptive Transients
• A Model for the 19th Century Eruption of Eta Carinae: CSM Interaction Like a Scaled-Down Type IIn Supernova
• Was the nineteenth century giant eruption of Eta Carinae a merger event in a triple system?
• The Purple Haze of Eta Carinae: Binary-Induced Variability?
• The Departure of Eta Carinae from Axisymmetry and the Binary Hypothesis
• Possible Implications of Mass Accretion in Eta Carinae
• Doppler tomography of the Little Homunculus: High resolution spectra of [Fe II] 16435 around Eta Carinae
• Identification of Emission Lines in the Low-Ionization Strontium Filament Near Eta Carinae
• The formation of stars in groups
• Ancient eruptions of Eta Carinae: A tale written in proper motions
• Why a Single-Star Model Cannot Explain the Bipolar Nebula of Eta Carinae
• The Structure of the Homunculus. II. Modeling the physical conditions in Eta Car's molecular shell
• Episodic Post-Shock Dust Formation in the Colliding Winds of Eta Carinae
• He II 4686 in eta Carinae: collapse of the wind-wind collision region during periastron passage
• Is Eta Carinae a fast rotator, and how much does the companion influence the inner wind structure?
• Asymmetry in the Outburst of SN 1987A Detected Using Light Echo Spectroscopy
• The fossil wind structures of Eta Carinae: changes across on 5.54-year cycle
• Light Echoes from Eta Carinae's Great Eruption: Spectrophotometric Evolution and the Rapid Formation of Nitrogen-rich Molecules
• HH 666: Different kinematics from Hα and [Fe II] emission provide a missing link between jets and outflows
• Cleaning up Eta Carinae: Detection of Ammonia in the Homunculus
• On the Interpretation of Supernova Light Echo Profiles and Spectra
• The Spectral Temperature of Optically Thick Outflows with Application to Light Echo Spectra from $\eta$~Carinae's Giant Eruption
• Molecules in η Carinae
• Penetrating the Homunculus -- Near-Infrared Adaptive Optics Images of Eta Carinae
• VLTI-AMBER velocity-resolved aperture-synthesis imaging of Eta Carinae with a spectral resolution of 12000. Studies of the primary star wind and innermost wind-wind collision
• Dust formation by the colliding-wind WC5+O9 binary WR19 at periastron passage
• Near-Infrared Evidence for a Sudden Temperature Increase in Eta Carinae
• Kinematics of powerful jets from intermediate-mass protostars in the Carina nebula
• Dissecting a SN impostor's circumstellar medium: MUSEing about the SHAPE of eta Car's outer ejecta
• Spatial distribution and kinematics of the molecular material associated with $\eta$ Carinae
• Comparison of Diversity of Type IIb Supernovae with Asymmetry in Cassiopeia A Using Light Echoes
• Numerical simulations of wind-equatorial gas interaction in eta Carinae

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• Common Envelope Shaping of Planetary Nebulae
• Light-echoes from the plateau in Eta Carinae's Great Eruption reveal a two-stage shock-powered event
• Simulating the formation of $\eta$ Carinae's surrounding nebula through unstable triple evolution and stellar merger-induced eruption
• Exceptionally fast ejecta seen in light echoes of Eta Carinae's Great Eruption
• Distinguishing Circumstellar from Stellar Photometric Variability in Eta Carinae
• A disrupted molecular torus around Eta Carinae as seen in 12CO with ALMA
• Luminous Blue Variables
• Ultraviolet Mg II emission from fast neutral ejecta around Eta Carinae
• A six year image-subtraction light curve of SN 2010jl
• Long-term evolution in ionization of ejecta illuminated by Eta Carinae