Cococubed.com Micronovae
Home Astronomy research   Software Infrastructure:      MESA      FLASH-X      STARLIB      MESA-Web      starkiller-astro      My instruments   White dwarf supernova:      Stable nickel production      Remnant metallicities      Colliding white dwarfs      Merging white dwarfs      Ignition conditions      Metallicity effects      Central density effects      Detonation density effects      Tracer particle burning      Subsonic burning fronts      Supersonic burning fronts      W7 profiles   Massive star supernova:      Rotating progenitors      3D evolution      26Al & 60Fe      44Ti, 60Co & 56Ni      Yields of radionuclides      Effects of 12C +12C      SN 1987A light curve      Constraints on Ni/Fe ratios      An r-process   Neutron Stars and Black Holes:      Black Hole mass spectrum      Compact object IMF      He burn on neutron stars   Stars:      Variable white dwarfs      Pop III with JWST      Micronovae      Neutrino HR diagram      Monte Carlo massive stars      Pre-supernova neutrinos      Pre-supernova variations      Monte Carlo white dwarfs      SAGB stars      Nugrid Yields I      Classical novae      He shell convection      Presolar grains      BBFH at 40 years   Chemical Evolution:      Iron Pseudocarbynes      Radionuclides in the 2020s      Hypatia catalog      Zone models H to Zn      Mixing ejecta      γ-rays within 100 Mpc   Thermodynamics & Networks      Stellar EOS      12C(α,γ)16O Rate      Proton-rich NSE      Reaction networks      Bayesian reaction rates   Verification Problems:      Validating an astro code      Su-Olson      Cog8      Mader      RMTV      Sedov      Noh Software instruments Presentations Illustrations cococubed YouTube Bicycle adventures Public Outreach Education materials 2022 ASU Solar Systems Astronomy 2022 ASU Energy in Everyday Life AAS Journals AAS YouTube 2022 Earendel, A Highly Magnified Star 2022 TV Columbae, Micronova 2022 White Dwarfs and 12C(α,γ)16O 2022 MESA VI 2022 MESA in Don't Look Up 2022 MESA Marketplace 2012-2023 MESA Schools 2022 MESA Classroom 2021 Bill Paxton, Tinsley Prize Contact: F.X.Timmes my one page vitae, full vitae, research statement, and teaching statement.	Localized thermonuclear bursts from accreting magnetic white dwarfs (2022) Nova explosions are caused by global thermonuclear runaways triggered in the surface layers of accreting white dwarfs. It has been predicted that localised thermonuclear bursts on white dwarfs can also take place, similar to Type I X-ray bursts observed in accreting neutron stars. Unexplained rapid bursts from the binary system TV Columbae, in which mass is accreted onto a moderately-strong magnetised white dwarf from a low-mass companion, have been observed on several occasions in the past ≈40 years. During these bursts the optical/UV luminosity increases by a factor of >3 in less than an hour and fades over ≈10 hours. Fast outflows have been observed in UV spectral lines$^{7}$, with velocities >3500 km/s, comparable to the escape velocity from the white dwarf surface. In this article, we report on optical bursts observed in TV Columbae as well as in two additional accreting systems, EI Ursae Majoris and ASASSN$-$19bh. The bursts have a total energy ≈10-6 those of classical nova explosions ("micronovae"), and bear a strong resemblance to Type I X-ray bursts. We exclude accretion or stellar magnetic reconnection events as their origin and suggest thermonuclear runaway events in magnetically-confined accretion columns as a viable explanation. This article, made some news and some more news. Optical brightness variations in TV Columbae (a) TESS lightcurve, (b-d) 6.8 h of data around the three detected rapid bursts, with individual bursts yielding integrated energies of 0.9e38 erg (b), 1.6e38 erg (c) and 1e38 erg (d).