Projektbeschreibung
Entwicklung von Doppelsternsystemen im neuen Licht
Mit der gemeinsamen Hülle (Common-Envelope) wird eine kurze, aber wichtige Phase in der Evolution eines Doppelsternsystems beschrieben, in der zwei Sterne stark miteinander wechselwirken und entweder große Mengen an Masse verlieren oder zu einem einzigen Objekt verschmelzen. Erwartungsgemäß begleitet zunehmende Leuchtkraft die gemeinsame Hülle, so dass ein rotes transientes Ereignis sichtbar wird. Mehrere rote Transienten stellen jedoch das vorherrschende Common-Envelope-Paradigma in Frage. Das EU-finanzierte Projekt Cat-In-hAT wird nun eine neue Variante der Magnetohydrodynamik einsetzen, um die dreidimensionale Dynamik einer gemeinsamen Hülle vom Beginn des Massenverlustes bis zur Überrestphase zu erforschen. Das Projekt wird durch Betrachtung der Auswirkungen auf ein breites Spektrum astrophysikalischer Objekte weitere Einblicke in dieses wichtige Phänomen gewinnen.
Ziel
"One of the crucial formation channels of compact object binaries, including sources of gravitational waves, critically depends on catastrophic binary interactions accompanied by the loss of mass, angular momentum, and energy (""common envelope"" evolution - CEE). Despite its importance, CEE is perhaps the least understood major phase of binary star evolution and progress in this area is urgently needed to interpret observations from the new facilities (gravitational wave detectors, time-domain surveys).
Recently, the dynamical phase of the CEE has been associated with a class of transient brightenings exhibiting slow expansion velocities and copious formation of dust and molecules (red transients - RT). A number of RT features, especially the long timescale of mass loss, challenge the existing CEE paradigm.
Motivated by RT, I will use a new variant of magnetohydrodynamics to comprehensively examine the 3D evolution of CEE from the moment when the mass loss commences to the remnant phase. I expect to resolve the long timescales observed in RT, characterize binary stability in 3D with detailed microphysics, illuminate the fundamental problem of how is orbital energy used to unbind the common envelope in a regime that was inaccessible before, and break new ground on the amplification of magnetic fields during CEE.
I will establish RT as an entirely new probe of the CEE physics by comparing my detailed theoretical predictions of light curves from different viewing angles, spectra, line profiles, and polarimetric signatures with observations of RT. I will accomplish this by coupling multi-dimensional moving mesh hydrodynamics with radiation, dust formation, and chemical reactions. Finally, I will examine the physical processes in RT remnants on timescales of years to centuries after the outburst to connect RT with the proposed merger products and to identify them in time-domain surveys.
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Wissenschaftliches Gebiet
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Finanzierungsplan
ERC-STG - Starting GrantGastgebende Einrichtung
116 36 Praha 1
Tschechien