Light-echoes from the plateau in Eta Carinae's Great Eruption reveal a two-stage shock-powered event

Abstract

We present multi-epoch photometry and spectroscopy of a light echo from eta Carinae's 19th century Great Eruption. This echo shows a steady decline over a decade, sampling the 1850s plateau of the eruption. Spectra show the bulk outflow speed increasing from 150 km/s at early times, up to 600 km/s in the plateau. Later phases also develop remarkably broad emission wings indicating mass accelerated to more than 10,000 km/s. Together with other clues, this provides direct evidence for an explosive ejection. This is accompanied by a transition from narrow absorption lines to emission lines, often with broad P Cygni profiles. These changes imply that the pre-1845 luminosity spikes are distinct from the 1850s plateau. The key reason for this change may be that shock interaction dominates the plateau. The spectral evolution of eta Car closely resembles that of UGC2773-OT, which had clear signatures of shock interaction. We propose a 2-stage scenario for eta Car's eruption: (1) a slow outflow in the decades before the eruption, driven by binary interaction that produced a dense equatorial outflow, followed by (2) explosive energy injection that drove CSM interaction, powering the plateau and sweeping slower CSM into a fast shell that became the Homunculus. We discuss how this sequence could arise from a stellar merger in a triple system, leaving the eccentric binary seen today. This gives a self-consistent scenario that may explain interacting transients across a wide range of initial mass.

arXiv commentAccepted by MNRAS. 36 pages, 17 figures

References in corpus (114)

• Binary interaction dominates the evolution of massive stars
• The Nucleosynthetic Signature of Population III
• Cosmic-Ray Rejection by Laplacian Edge Detection
• Las Cumbres Observatory Global Telescope Network
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• The Dark Energy Camera
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
• The Eccentric Kozai-Lidov Effect and Its Applications
• Pulsational Pair-Instability Supernovae
• Pulsational pair instability as an explanation for the most luminous supernovae
• V1309 Scorpii: merger of a contact binary
• Tertiary companions to close spectroscopic binaries
• On the role of continuum-driven eruptions in the evolution of very massive stars and Population III stars
• Wave-Driven Mass Loss in the Last Year of Stellar Evolution: Setting the Stage for the Most Luminous Core-Collapse Supernovae
• A spectroscopic survey on the multiplicity of high-mass stars
• On the triple origin of blue stragglers
• Interacting Supernovae and Supernova Impostors. SN 2009ip, is this the end?
• 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
• Detailed Analysis of Early to Late-Time Spectra of Supernova 1993J
• Preparing for an Explosion: Hydrodynamic Instabilities and Turbulence in Presupernovae
• SN 2006tf: Precursor Eruptions and the Optically Thick Regime of Extremely Luminous Type IIn Supernovae
• An energetic stellar outburst accompanied by circumstellar light echoes
• Discovery of Precursor LBV Outbursts in Two Recent Optical Transients: The Fitfully Variable Missing Links UGC 2773-OT and SN 2009ip
• Pre-Supernova Outbursts via Wave Heating in Massive Stars I: Red Supergiants
• A Porosity-Length Formalism for Photon-Tiring-Limited Mass Loss from Stars Above the Eddington Limit
• The type IIn supernova 1994W: evidence for the explosive ejection of a circumstellar envelope
• In Hot Pursuit of the Hidden Companion of Eta Carinae: An X-ray Determination of the Wind Parameters
• Shell-shocked diffusion model for the light curve of SN2006gy
• Discovery of the Dust-Enshrouded Progenitor of SN 2008S with Spitzer
• Setting the Stage for Circumstellar Interaction in Core-Collapse Supernovae II: Wave-Driven Mass Loss in Supernova Progenitors
• Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey
• A New Class of Luminous Transients and A First Census of Their Massive Stellar Progenitors
• SN 2008S: an electron capture SN from a super-AGB progenitor?
• A Census of the Carina Nebula. I: Cumulative Energy Input from Massive Stars
• Effects of Rotation on the Minimum Mass of Primordial Progenitors of Pair Instability Supernovae
• Latitude-dependent effects in the stellar wind of Eta Carinae
• The Diversity of Massive Star Outbursts I: Observations of SN 2009ip, UGC 2773 OT2009-1, and Their Progenitors
• Luminous Blue Variables and superluminous supernovae from binary mergers
• The 2008 Luminous Optical Transient in the Nearby Galaxy NGC 300
• Identification of the Long-Sought Common-Envelope Events
• Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)
• Echoes from Ancient Supernovae in the Large Magellanic Cloud
• An Updated Look at Binary Characteristics of Massive Stars in the Cygnus OB2 Association
• SN 2009ip and SN 2010mc: Core-collapse Type IIn supernovae arising from blue supergiants
• An Intermediate Luminosity Transient in NGC300: The Eruption of a Dust-Enshrouded Massive Star
• The Mass-Loss Induced Eccentric Kozai Mechanism: A New Channel for the Production of Close Compact Object-Stellar Binaries
• Stellar Mergers Are Common
• Cool and Luminous Transients from Mass-Losing Binary Stars
• Microslit Nod-shuffle Spectroscopy - a technique for achieving very high densities of spectra
• V1309 SCO - Understanding a merger
• SN 2008S: A Cool Super-Eddington Wind in a Supernova Impostor
• The triple evolution dynamical instability: Stellar collisions in the field and the formation of exotic binaries
• Binary Stellar Mergers with Marginally-Bound Ejecta: Excretion Disks, Inflated Envelopes, Outflows, and their Luminous Transients
• Numerical simulations of super-luminous supernovae of type IIn
• The porous atmosphere of eta Carinae
• Super-Eddington Stellar Winds Driven by Near-Surface Energy Deposition
• Common Envelope ejection for a Luminous Red Nova in M101
• Shock-powered light curves of luminous red novae as signatures of pre-dynamical mass loss in stellar mergers
• 3D modelling of the colliding winds in Eta Carinae - evidence for radiative inhibition
• 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
• Numerical models of collisions between core-collapse supernovae and circumstellar shells
• Multiple Major Outbursts from a Restless Luminous Blue Variable in NGC 3432
• 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
• Pre-explosion spiral mass loss of a binary star merger
• High-excitation emission lines near eta Carinae, and its likely companion star
• The Binarity of Eta Carinae Revealed from Photoionization Modeling of the Spectral Variability of the Weigelt Blobs B and D
• Giant Outbursts of Luminous Blue Variables and the Formation of the Homunculus Nebula Around eta Carinae
• A Census of the Carina Nebula -- II. Energy Budget and Global Properties of the Nebulosity
• 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
• The Astrophysical Implications of Dust Formation During The Eruptions of Hot, Massive Stars
• Modeling the RXTE light curve of $\eta$ Carinae from a 3-D SPH simulation of its binary wind collision
• Burying a Binary: Dynamical Mass Loss and a Continuous Optically-Thick Outflow Explain the Candidate Stellar Merger V1309 Scorpii
• Almost Gone: SN~2008S and NGC~300 2008OT-1 are Fainter than their Progenitors
• Explosions Triggered by Violent Binary-Star Collisions: Application to Eta Carinae and other Eruptive Transients
• A Spitzer/IRS Spectrum of the 2008 Luminous Transient in NGC 300: Connection to Proto-Planetary Nebulae
• Secular dynamics in hierarchical three-body systems with mass loss and mass transfer
• Nitrogen and Oxygen Abundance Variations in the Outer Ejecta of Eta Carinae: Evidence for Recent Chemical Enrichment
• 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 peculiar nova V1309 Sco/Nova Sco 2008: A candidate twin of V838 Mon
• Opening the Treasure Chest: A Newborn Star Cluster Emerges from its Dust Pillar in Carina
• The Departure of Eta Carinae from Axisymmetry and the Binary Hypothesis
• Possible Implications of Mass Accretion in Eta Carinae
• Numerical simulations of continuum-driven winds of super-Eddington stars
• Identification of Emission Lines in the Low-Ionization Strontium Filament Near Eta Carinae
• Why a Single-Star Model Cannot Explain the Bipolar Nebula of Eta Carinae
• Ancient eruptions of Eta Carinae: A tale written in proper motions
• The Structure of the Homunculus. II. Modeling the physical conditions in Eta Car's molecular shell
• Additional Massive Binaries in the Cygnus OB2 Association
• Stellar orbit evolution in close circumstellar disc encounters
• Super-Eddington stellar winds: unifying radiative-enthalpy vs. flux-driven models
• The Persistent Eruption of UGC~2773-OT: Finally, a Decade-Long Extragalactic Eta Carinae Analog
• Carina's Defiant Finger: HST Observations of a Photoevaporating Globule in NGC3372
• On the behaviour of stellar winds that exceed the photon-tiring limit
• Exceptionally fast ejecta seen in light echoes of Eta Carinae's Great Eruption
• Shock Dynamics in Stellar Outbursts: I. Shock formation
• Light Echoes from Eta Carinae's Great Eruption: Spectrophotometric Evolution and the Rapid Formation of Nitrogen-rich Molecules
• Near-infrared integral field spectroscopy of the Homunculus nebula around Eta Carinae using Gemini/CIRPASS
• Evolution of the Reverse Shock Emission from SNR 1987A
• [TiII] and [NiII] emission from the strontium filament of eta Carinae
• The Great Eruption of Eta Carinae
• The reverse shock of SNR1987A at 18 years after outburst
• The Structure of the Homunculus. III. Forming a Disk and Bipolar Lobes in a Rotating Surface Explosion
• A disrupted molecular torus around Eta Carinae as seen in 12CO with ALMA
• The Spectral Temperature of Optically Thick Outflows with Application to Light Echo Spectra from $\eta$~Carinae's Giant Eruption
• Modelling the Central Constant Emission X-ray component of eta Carinae
• Eta Carinae's Thermal X-ray Tail Measured with XMM-Newton and NuSTAR
• A moderately precise dynamical age for the Homunculus of Eta Carinae based on 13 years of HST imaging
• G-Mode Excitation During the Pre-explosive Simmering of Type Ia Supernovae
• Dissecting a SN impostor's circumstellar medium: MUSEing about the SHAPE of eta Car's outer ejecta

Cited by in corpus (48)

• Stellar triples on the edge; Comprehensive overview of the evolution of destabilised triples leading to stellar and binary exotica
• Long-term evolution of a magnetic massive merger product
• Simulating the formation of $\eta$ Carinae's surrounding nebula through unstable triple evolution and stellar merger-induced eruption
• On the Gaia DR2 distances for Galactic Luminous Blue Variables
• Multiplicity of Galactic Luminous Blue Variable stars
• Hydrodynamical simulations and similarity relations for eruptive mass loss from massive stars
• SN 2009ip after a decade: The luminous blue variable progenitor is now gone
• Supernova Interaction with a Dense Detached Shell in SN 2001em
• High-resolution spectroscopy of SN 2017hcc and its blueshifted line profiles from post-shock dust formation
• Constraining the Overcontact Phase in Massive Binary Evolution I. Mixing in V382 Cyg, VFTS 352, and OGLE SMC-SC10 108086
• Exceptionally fast ejecta seen in light echoes of Eta Carinae's Great Eruption
• Photometric and spectroscopic evolution of the interacting transient AT 2016jbu (Gaia16cfr)
• A systematic reclassification of type IIn supernovae
• Kinematics of Mass Loss from the Outer Lagrange Point L2
• Progenitor, environment, and modelling of the interacting transient, AT 2016jbu (Gaia16cfr)
• Supernova explosions interacting with aspherical circumstellar material: implications for light curves, spectral line profiles, and polarization
• Distinguishing Circumstellar from Stellar Photometric Variability in Eta Carinae
• An Exceptional Dimming Event for a Massive, Cool Supergiant in M51
• PION: Simulating bow shocks and circumstellar nebulae
• The Blue Supergiant Progenitor of the Supernova Imposter AT~2019krl
• Constraining the overcontact phase in massive binary evolution -- II. Period stability of known O+O overcontact systems
• Unveiling the Nature of SN 2011fh: a Young and Massive Star Gives Rise to a Luminous SN 2009ip-like Event
• SN 1961V: A Pulsational Pair-Instability Supernova
• Repeating periodic eruptions of the supernova impostor SN 2000ch
• Eta Carinae & the Homunculus: Far Infrared, Sub-millimeter Spectral Lines
• A Systematic Study Of Superluminous Supernova Lightcurve Models Using Clustering
• Fast Ejecta Resulted from Jet-Wind Interaction in the Great Eruption of Eta Carinae
• Spectroscopic Signatures of the Vanishing Natural Coronagraph of eta Carinae
• CO, Water, and Possible Methanol in Eta Carinae Approaching Periastron
• The orbital kinematics of eta Carinae over three periastra with a possible detection of the elusive secondary's motion
• Luminous Blue Variables
• First detection of silicon-bearing molecules in $\eta$ Car
• Kinematics of Luminous Blue Variables in the Large Magellanic Cloud
• Multiple giant eruptions and X-ray emission in the recoiling AGN/LBV candidate SDSS1133
• Ultraviolet Mg II emission from fast neutral ejecta around Eta Carinae
• Binary imposters: Mergers in massive hierarchical triple stars
• A warm molecular ring in AG Car: composing the mass-loss puzzle
• Towards a consistent model of the hot quadruple system HD 93206 = QZ Carinæ: II. N-body model
• Hidden shock powering the peak of SN 2020faa
• The bright, dusty aftermath of giant eruptions & H-rich supernovae. Late interaction of supernova shocks & dusty circumstellar shells
• Numerical simulations of the 1840s great eruption of $\eta$ Carinae: I. Revisiting the explosion scenario
• Fading Echoes of Interaction: Probing Centuries of Preexplosion Mass-Loss in Four Type IIn Supernovae
• Discovery of a 310-day Period from the Enshrouded Massive System NaSt1 (WR 122)
• A Search for Supernova Light Echoes in NGC 6946 with SITELLE
• The Age of the R127 & R128 Clusters: Implications for the LBV
• Hubble Space Telescope Imaging Reveals That SN 2015bh Is Much Fainter than Its Progenitor
• When Stars Mimic Monsters: Spectral Evidence for an $\eta$ Carinae-like Giant Eruption in SBS 0335$-$052 E
• Spectroscopy of AT 2016blu's recurring supernova impostor outbursts