2019/02/17 by S. P. Owocki, Stanley P. Owocki, Ryo Hirai +4 · 40 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Ejecta #Energy (signal processing) #Exponential function #Geometry #Kinetic energy #Light curve #Physics #Quantum mechanics #RADIUS #Scale height #Scaling #Star (game theory) #Stars #Stellar, planetary, and galactic studies #Supernova #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stz461
published in Monthly Notices of the Royal Astronomical Society 485(1), 988-1000 (Oxford University Press) · 14 Pages, 12 figures; MNRAS, in press
arxiv created 2019/02/17 · openalex publication_date 2019/02/18 · arxiv updated 2019/02/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Motivated by the eruptive mass-loss inferred from Luminous Blue Variable (LBV) stars, we present 1D hydrodynamical simulations of the response from sudden energy injection into the interior of a very massive (|100 \rm M_\odot|) star. For a fiducial case with total energy addition set to a factor f = 0.5 of the net stellar binding energy, and applied within the stellar envelope, we detail the dynamical response that leads to ejection of the outermost |7.2 \rm M_\odot|. We find that the ejecta’s variations in time t and radius r for the velocity v, density ρ, and temperature T are quite well fit by similarity forms in the variable r/t ≈ v. Specifically the scaled density follows a simple exponential decline ρt3 ∼ exp (− r/vot). This ‘exponential similarity’ leads to analytic scaling relations for total ejecta mass ΔM and kinetic energy ΔK that agree well with the hydrodynamical simulations, with the specific-energy-averaged speed related to the exponential scale speed vo through |v ≡ √(2 Δ K/Δ M) = √(12) v\rm o|, and a value comparable to the star’s surface escape speed, vesc. Models with energy added in the core develop a surface shock breakout that propels an initial, higher speed ejecta (>5000 km s−1), but the bulk of the ejected material still follows the same exponential similarity scalings with |v ≈ v\rm esc|. A broader parameter study examines how the ejected mass and energy depends on the energy-addition factor f, for three distinct model series that locate the added energy in either the core, envelope, or near-surface. We conclude by discussing the relevance of these results for understanding LBV outbursts and other eruptive phenomena, such as failed supernovae and pulsational pair instability events.