scholarly journals Disc formation and jet inclination effects in common envelopes

2020 ◽  
Vol 497 (2) ◽  
pp. 2057-2065 ◽  
Author(s):  
Diego López-Cámara ◽  
Enrique Moreno Méndez ◽  
Fabio De Colle
Keyword(s):  
Main Sequence ◽  
Three Dimensional ◽  
Compact Object ◽  
Main Sequence Stars ◽  
Common Envelope ◽  
Ejection Process ◽  
The Common ◽  
Red Giant ◽  
Hydrodynamical Simulations ◽  
Disc Formation

ABSTRACT The evolution and physics of the common envelope (CE) phase are still not well understood. Jets launched from a compact object during this stage may define the evolutionary outcome of the binary system. We focus on the case in which jets are launched from a neutron star (NS) engulfed in the outer layers of a red giant (RG). We run a set of three-dimensional hydrodynamical simulations of jets with different luminosities and inclinations. The luminosity of the jet is self-regulated by the mass accretion rate and an efficiency η. Depending on the value of η the jet can break out of the previously formed bulge (‘successful jet’) and aligns against the incoming wind, in turn, it will realign in favour of the direction of the wind. The jet varies in size and orientation and may present quiescent and active epochs. The inclination of the jet and the Coriolis and centrifugal forces, only slightly affect the global evolution. As the accretion is hypercritical, and the specific angular momentum is above the critical value for the formation of a disc, we infer the formation of a disc and launching of jets. The discs’ mass and size would be ∼10−2 M⊙ and ≳1010 cm, and it may have rings with different rotation directions. In order to have a successful jet from a white dwarf, the ejection process needs to be very efficient (η ∼ 0.5). For main-sequence stars, there is not enough energy reservoir to launch a successful jet.

scholarly journals Companion-launched jets and their effect on the dynamics of common envelope interaction simulations

2019 ◽  
Vol 488 (4) ◽  
pp. 5615-5632 ◽  
Author(s):  
Sagiv Shiber ◽  
Roberto Iaconi ◽  
Orsola De Marco ◽  
Noam Soker
Keyword(s):  
Three Dimensional ◽  
Gravitational Energy ◽  
Numerical Code ◽  
Binary Interaction ◽  
Giant Star ◽  
Common Envelope ◽  
The Common ◽  
Red Giant ◽  
Set Up ◽  
First Time

Abstract We conduct three-dimensional hydrodynamic simulations of the common envelope binary interaction and show that if the companion were to launch jets while interacting with the giant primary star’s envelope, the jets would remove a substantial fraction of the envelope’s gas. We use the set-up and numerical code of an earlier common envelope study that did not include jets, with a 0.88-M⊙, 83-R⊙ red giant star and a 0.3-M⊙ companion. The assumption is that the companion star accretes mass via an accretion disc that is responsible for launching the jets which, in the simulations, are injected numerically. For the first time we conduct simulations that include jets as well as the gravitational energy released by the inspiralling core-companion system. We find that simulations with jets unbind approximately three times as much envelope mass than identical simulations that do not include jets, though the total fraction of unbound gas remains below 50 per cent for these particular simulations. The jets generate high-velocity outflows in the polar directions. The jets also increase the final core-companion orbital separation and lead to a kick velocity of the core-companion binary system. Our results show that, if able to form, jets could play a crucial role in ejecting the envelope and in shaping the outflow.

scholarly journals Shaping Planetary Nebulae with Jets and the Grazing Envelope Evolution

Galaxies ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 26 ◽  
Author(s):  
Noam Soker
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Planetary Nebulae ◽  
The Other ◽  
High Rate ◽  
Main Sequence Stars ◽  
Common Envelope ◽  
Black Hole Binary ◽  
The Common ◽  
Star Binary

I argue that the high percentage of planetary nebulae (PNe) that are shaped by jets show that main sequence stars in binary systems can accrete mass at a high rate from an accretion disk and launch jets. Not only does this allow jets to shape PNe, but this also points to the importance of jets in other types of binary systems and in other processes. These processes include the grazing envelope evolution (GEE), the common envelope evolution (CEE), and the efficient conversion of kinetic energy to radiation in outflows. Additionally, the jets point to the possibility that many systems launch jets as they enter the CEE, possibly through a GEE phase. The other binary systems in which jets might play significant roles include intermediate-luminosity optical transients (ILOTs), supernova impostors (including pre-explosion outbursts), post-CEE binary systems, post-GEE binary systems, and progenitors of neutron star binary systems and black hole binary systems. One of the immediate consequences is that the outflow of these systems is highly-non-spherical, including bipolar lobes, jets, and rings.

scholarly journals Do instabilities in high-multiplicity systems explain the existence of close-in white dwarf planets?

2020 ◽  
Vol 501 (1) ◽  
pp. L43-L48
Author(s):  
R F Maldonado ◽  
E Villaver ◽  
A J Mustill ◽  
M Chávez ◽  
E Bertone
Keyword(s):  
Natural Condition ◽  
Atmospheric Pollution ◽  
Main Sequence ◽  
Planetary System ◽  
Dynamical Instability ◽  
Small Object ◽  
Main Sequence Stars ◽  
Common Envelope ◽  
Dwarf Planets ◽  
The Common

ABSTRACT We investigate the origin of close-in planets and related phenomena orbiting white dwarfs (WDs), which are thought to originate from orbits more distant from the star. We use the planetary architectures of the 75 multiple-planet systems (four, five, and six planets) detected orbiting main-sequence stars to build 750 dynamically analogous templates that we evolve to the WD phase. Our exploration of parameter space, although not exhaustive, is guided and restricted by observations and we find that the higher the multiplicity of the planetary system, the more likely it is to have a dynamical instability (losing planets, orbit crossing, and scattering), that eventually will send a planet (or small object) through a close periastron passage. Indeed, the fraction of unstable four- to six-planet simulations is comparable to the 25–50${{\ \rm per\ cent}}$ fraction of WDs having atmospheric pollution. Additionally, the onset of instability in the four- to six-planet configurations peaks in the first Gyr of the WD cooling time, decreasing thereafter. Planetary multiplicity is a natural condition to explain the presence of close-in planets to WDs, without having to invoke the specific architectures of the system or their migration through the von Zeipel–Lidov–Kozai effects from binary companions or their survival through the common envelope phase.

scholarly journals V471 Tauri and SuWt 2: The Exotic Descendants of Triple Systems?

2002 ◽  
Vol 187 ◽  
pp. 239-243 ◽  
Author(s):  
Howard E. Bond ◽  
M. Sean O’Brien ◽  
Edward M. Sion ◽  
Dermott J. Mullan ◽  
Katrina Exter ◽  
...  
Keyword(s):  
Main Sequence ◽  
Central Star ◽  
High Mass ◽  
Eclipsing Binary ◽  
Triple Systems ◽  
Common Envelope ◽  
Short Period ◽  
Efficiency Parameter ◽  
Hydrodynamical Simulations ◽  
Good Agreement

AbstractV471 Tauri is a short-period eclipsing binary, and a member of the Hyades. It is composed of a hot DA white dwarf (WD) and a cool main-sequence dK2 companion. HST radial velocities of the WD, in combination with the ground-based spectroscopic orbit of the K star, yield dynamical masses of MWD = 0.84 and MdK = 0.93 M⊙. During the UV observations we serendipitously detected coronal mass ejections from the K star, passing in front of the WD and appearing as sudden, transient metallic absorption. Eclipse timings show that the active dK star is 18% larger than a main-sequence star of the same mass, an apparent consequence of its extensive starspot coverage. The high Teff and high mass of the WD are paradoxical: the WD is the most massive in the Hyades, but also the youngest. A plausible scenario is that the progenitor system was a triple, with a close inner pair that merged after several × 108 yr to produce a single blue straggler. When this star evolved to the AGB phase, it underwent a common-envelope interaction with a distant dK companion, which spiraled down to its present separation and ejected the envelope. The common-envelope efficiency parameter, αCE, was of order 0.3–1.0, in good agreement with recent hydrodynamical simulations.SuWt 2 is a southern-hemisphere planetary nebula (PN) with an unusual ring-shaped morphology. The central star is an eclipsing binary with a period of 4.9 days. Surprisingly, the binary is composed of two main-sequence A-type stars with similar masses of ~ 2.5 M⊙. We discuss scenarios involving a third companion which ejected and ionizes the PN.WeBo 1 is a northern PN with a ring morphology remarkably similar to that of SuWt 2. Although we hoped that its central star would shed light on the nature of SuWt 2, it has proven instead to be a late-type barium star!

scholarly journals An Observational Evidence of the Common Envelope Phase

2004 ◽  
Vol 194 ◽  
pp. 37-38
Author(s):  
Marek J. Sarna ◽  
Jeremy J. Drake
Keyword(s):  
Abundance Ratio ◽  
Observational Evidence ◽  
Coronal Emission ◽  
X Ray ◽  
Common Envelope ◽  
Transmission Grating ◽  
Processed Material ◽  
The Common ◽  
Red Giant ◽  
First Time

AbstractChandra Low Energy Transmission Grating Spectrograph observations of the pre-cataclysmic binary V471 Tau have been used to estimate the C/N abundance ratio of the K dwarf component for the first time. While the white dwarf component dominates the spectrum longward of 50 Å, at shorter wavelengths the observed X-ray emission is entirely due to coronal emission from the K dwarf. The H-like 2p 2Р3/2, 1/2 → 1s 2S1/2 resonance lines of С and N yield an estimate of their logarithmic abundance ratio relative to the Sun of [C/N]= –0.38 ± 0.15—half of the currently accepted solar value. We interpret this result as the first clear observational evidence for the presumed common envelope phase of this system, during which the surface of the K dwarf was contaminated by CN-cycle processed material dredged up into the red giant envelope

scholarly journals SIMULATING THE COMMON ENVELOPE PHASE OF A RED GIANT USING SMOOTHED-PARTICLE HYDRODYNAMICS AND UNIFORM-GRID CODES

2011 ◽  
Vol 744 (1) ◽  
pp. 52 ◽  
Author(s):  
Jean-Claude Passy ◽  
Orsola De Marco ◽  
Chris L. Fryer ◽  
Falk Herwig ◽  
Steven Diehl ◽  
...  
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Uniform Grid ◽  
Common Envelope ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Grid Codes ◽  
The Common ◽  
Red Giant
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