scholarly journals Astrophysical Significance of Asymptotic Giant Branch Stellar Wind Energies Recorded in Meteoritic SiC Grains

2004 ◽  
Vol 607 (1) ◽  
pp. 611-619 ◽  
Author(s):  
A. B. Verchovsky ◽  
I. P. Wright ◽  
C. T. Pillinger
Keyword(s):  
Stellar Wind ◽  
Asymptotic Giant Branch ◽  
Astrophysical Significance

scholarly journals AGB winds in interacting binary stars

2020 ◽  
Vol 493 (2) ◽  
pp. 2606-2617 ◽  
Author(s):  
Luis C Bermúdez-Bustamante ◽  
G García-Segura ◽  
W Steffen ◽  
L Sabin
Keyword(s):  
Radiation Pressure ◽  
Stellar Wind ◽  
Binary Stars ◽  
Massive Star ◽  
Density Ratio ◽  
Asymptotic Giant Branch ◽  
Surface Layers ◽  
Outflow Velocity ◽  
Analytical Formulae ◽  
Set Up

ABSTRACT We perform numerical simulations to investigate the stellar wind from interacting binary stars. Our aim is to find analytical formulae describing the outflow structure. In each binary system the more massive star is in the asymptotic giant branch (AGB) and its wind is driven by a combination of pulsations in the stellar surface layers and radiation pressure on dust, while the less massive star is in the main sequence. Time averages of density and outflow velocity of the stellar wind are calculated and plotted as profiles against distance from the centre of mass and colatitude angle. We find that mass is lost mainly through the outer Lagrangian point L2. The resultant outflow develops into a spiral at low distances from the binary. The outflowing spiral is quickly smoothed out by shocks and becomes an excretion disc at larger distances. This leads to the formation of an outflow structure with an equatorial density excess, which is greater in binaries with smaller orbital separation. The pole-to-equator density ratio reaches a maximum value of ∼105 at Roche lobe overflow state. We also find that the gas stream leaving L2 does not form a circumbinary ring for stellar mass ratios above 0.78, when radiation pressure on dust is taken into account. Analytical formulae are obtained by curve fitting the two-dimensional, azimuthally averaged density and outflow velocity profiles. The formulae can be used in future studies to set-up the initial outflow structure in hydrodynamic simulations of common-envelope evolution and formation of planetary nebulae.

scholarly journals SN 2018zd: an unusual stellar explosion as part of the diverse Type II Supernova landscape

2020 ◽  
Vol 498 (1) ◽  
pp. 84-100 ◽  
Author(s):  
Jujia Zhang ◽  
Xiaofeng Wang ◽  
Vinkó József ◽  
Qian Zhai ◽  
Tianmeng Zhang ◽  
...  
Keyword(s):  
Temperature Rise ◽  
Stellar Wind ◽  
Radioactive Decay ◽  
Vital Role ◽  
Asymptotic Giant Branch ◽  
Expansion Velocity ◽  
Spectral Features ◽  
Asymptotic Giant Branch Star ◽  
Significant Temperature ◽  
Transition Event

ABSTRACT We present extensive observations of SN 2018zd covering the first ∼450 d after the explosion. This SN shows a possible shock-breakout signal ∼3.6 h after the explosion in the unfiltered light curve, and prominent flash-ionization spectral features within the first week. The unusual photospheric temperature rise (rapidly from ∼12 000 to above 18 000 K) within the earliest few days suggests that the ejecta were continuously heated. Both the significant temperature rise and the flash spectral features can be explained by the interaction of the SN ejecta with the massive stellar wind ($0.18^{+0.05}_{-0.10}\, \rm M_{\odot }$), which accounts for the luminous peak ($L_{\rm max} = [1.36\pm 0.63] \times 10^{43}\, \rm erg\, s^{-1}$) of SN 2018zd. The luminous peak and low expansion velocity (v ≈ 3300 km s−1) make SN 2018zd like a member of the LLEV (luminous SNe II with low expansion velocities) events originating due to circumstellar interaction. The relatively fast post-peak decline allows a classification of SN 2018zd as a transition event morphologically linking SNe IIP and SNe IIL. In the radioactive-decay phase, SN 2018zd experienced a significant flux drop and behaved more like a low-luminosity SN IIP both spectroscopically and photometrically. This contrast indicates that circumstellar interaction plays a vital role in modifying the observed light curves of SNe II. Comparing nebular-phase spectra with model predictions suggests that SN 2018zd arose from a star of $\sim 12\, \rm M_{\odot }$. Given the relatively small amount of 56Ni ($0.013\!-\!0.035 \rm M_{\odot }$), the massive stellar wind, and the faint X-ray radiation, the progenitor of SN 2018zd could be a massive asymptotic giant branch star that collapsed owing to electron capture.

scholarly journals Formation of Interstellar Bubble: A Time Dependent Numerical Simulation

1970 ◽  
Vol 6 (6) ◽  
pp. 8-15
Author(s):  
B Aryal ◽  
A Devkota ◽  
R Weinberger
Keyword(s):  
Interstellar Medium ◽  
Stellar Wind ◽  
Planetary Nebula ◽  
Mass Loss Rate ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Star ◽  
Scientific World ◽  
Three Phase ◽  
Good Environment ◽  
Branch Star

We present results of the numerical simulations for the first 105 years of the development of spherically symmetric interstellar bubbles. We have assumed three phase interstellar medium (ISM) model and estimated the size of the interstellar bubbles (ISB). Our results are based on calculations including 106 virtual stellar wind particles. We discuss the result in the context of Asymptotic Giant Branch (AGB) star, Proto-Planetary Nebula (PPN) phase and Relativistic Wind (RW) star. The size of the ISB is found 0.14 pc to 9.03 pc in the case of AGB (Asymptotic Giant Branch) star. This size increases for the PPN and RW phase to 0.64 - 40.28 pc and 2.83 pc - 178.12 pc, respectively. It is found that the ISB can survive in the case of cold and warm interstellar medium. In the hot ISM, the ISB can not be formed due to the AGB wind. The bubble can survive in the case of PPN phase stellar wind for all kinds of the ISM. In addition, we found that the bubble can be formed in the case of RW when the ISM is hot. In the cold ISM, the ISB can not be formed due to the RW. In the warm ISM, bubble can be formed due to the relativistic (pulsar) wind if the mass loss rate is extremely high. In the warm ISM, the overall size of the bubble increases but do not exceed the recommended limit. Our result indicates that the hot ISM can not be considered as a good environment for the existence of the ISB. The size of the bubble exceeds the recommended limit (i.e., 1 to 5 kpc) in both the PPN and RW phase. However, suitable AGB wind can trigger the environment for a bubble in the hot ISM. The results of this work should be compared with the observations in the future. Key words: Interstellar medium; Stellar wind; Planetary nebula; Pulsar. DOI: 10.3126/sw.v6i6.2626 Scientific World, Vol. 6, No. 6, July 2008 8-15

scholarly journals X-ray Shaping of Planetary Nebulae

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 98
Author(s):  
Martín Guerrero
Keyword(s):  
Stellar Wind ◽  
Essential Role ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Stellar Winds ◽  
Physical Processes ◽  
X Ray ◽  
Hot Gas ◽  
Energy And Momentum ◽  
Central Stars

The stellar winds of the central stars of planetary nebulae play an essential role in the shaping of planetary nebulae. In the interacting stellar winds model, the fast stellar wind injects energy and momentum, which are transferred to the nebular envelope through an X-ray-emitting hot bubble. Together with other physical processes, such as the ionization of the nebular envelope, the asymmetrical mass-loss in the asymptotic giant branch (AGB), and the action of collimated outflows and magnetic fields, the pressurized hot gas determines the expansion and evolution of planetary nebulae. Chandra and XMM-Newton have provided us with detailed information of this hot gas. Here in this talk I will review our current understanding of the effects of the fast stellar wind in the shaping and evolution of planetary nebulae and give some hints of the promising future of this research.

scholarly journals Isotopic Compositions of Ruthenium Predicted from the NuGrid Project

2022 ◽  
Vol 924 (2) ◽  
pp. 88
Author(s):  
Seonho Kim ◽  
Kwang Hyun Sung ◽  
Kyujin Kwak
Keyword(s):  
Stellar Wind ◽  
Asymptotic Giant Branch ◽  
Lower Mass ◽  
Low Mass Stars ◽  
Isotopic Compositions ◽  
Carbon Abundance ◽  
Wide Range ◽  
Low Metallicity ◽  
Low Mass

Abstract The isotopic compositions of ruthenium (Ru) are measured from presolar silicon carbide (SiC) grains. In a popular scenario, the presolar SiC grains formed in the outskirt of an asymptotic giant branch (AGB) star, left the star as a stellar wind, and joined the presolar molecular cloud from which the solar system formed. The Ru isotopes formed inside the star, moved to the stellar surface during the AGB phase, and were locked into the SiC grains. Following this scenario, we analyze the Nucleosynthesis Grid (NuGrid) data, which provide the abundances of the Ru isotopes in the stellar wind for a set of stars in a wide range of initial masses and metallicities. We apply the C > O (carbon abundance larger than the oxygen abundance) condition, which is commonly adopted for the condition of the SiC formation in the stellar wind. The NuGrid data confirm that SiC grains do not form in the winds of massive stars. The isotopic compositions of Ru in the winds of low-mass stars can explain the measurements. We find that lower-mass stars (1.65 M ☉ and 2 M ☉) with low metallicity (Z = 0.0001) can explain most of the measured isotopic compositions of Ru. We confirm that the abundance of 99 Ru inside the presolar grain includes the contribution from the in situ decay of 99 Tc. We also verify our conclusion by comparing the isotopic compositions of Ru integrated over all the pulses with those calculated at individual pulses.

The Effect of Helium Shell Flashes on Asymptotic Giant Branch Evolution

1992 ◽  
Vol 10 (1) ◽  
pp. 30-32 ◽  
Author(s):  
E. Vassiliadis ◽  
P.R. Wood
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Line Emission ◽  
Emission Spectra ◽  
Asymptotic Giant Branch ◽  
Natural Consequence ◽  
Intermediate Mass ◽  
Loss Process ◽  
Intermediate Mass Stars

AbstractMass-loss has been incorporated into a series of evolutionary calculations of low to intermediate mass stars during Asymptotic Giant Branch (AGB) evolution. When helium shell flashes occur a superwind phase is a natural consequence of the mass-loss process. The structure of the stellar wind envelopes that result has been computed. The models may explain some previously curious features seen in OH/IR and CO line emission spectra.

Observations of High Rotational CO Lines in Post–Asymptotic Giant Branch Stars and Planetary Nebulae

1997 ◽  
Vol 476 (1) ◽  
pp. 319-326 ◽  
Author(s):  
K. Justtanont ◽  
A. G. G. M. Tielens ◽  
C. J. Skinner ◽  
Michael R. Haas
Keyword(s):  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Giant Branch Stars

scholarly journals Carbon stars as standard candles – II. The median J magnitude as a distance indicator

2020 ◽  
Vol 501 (1) ◽  
pp. 933-947
Author(s):  
Javiera Parada ◽  
Jeremy Heyl ◽  
Harvey Richer ◽  
Paul Ripoche ◽  
Laurie Rousseau-Nepton
Keyword(s):  
Luminosity Function ◽  
Asymptotic Giant Branch ◽  
Distance Modulus ◽  
Asymptotic Giant Branch Stars ◽  
Luminosity Functions ◽  
Best Fitting ◽  
Distance Indicator ◽  
Ngc 6822 ◽  
The Given ◽  
Giant Branch Stars

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

scholarly journals Asteroseismology of luminous red giants with Kepler. II. Dependence of mass loss on pulsations and radiation

2020 ◽  
Author(s):  
Jie Yu ◽  
Saskia Hekker ◽  
Timothy R Bedding ◽  
Dennis Stello ◽  
Daniel Huber ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Loss Rate ◽  
Asymptotic Giant Branch ◽  
Red Giants ◽  
Asymptotic Giant Branch Stars ◽  
Chemical Enrichment ◽  
Dust Mass ◽  
Red Giant ◽  
The Masses ◽  
Loss Rates

Abstract Mass loss by red giants is an important process to understand the final stages of stellar evolution and the chemical enrichment of the interstellar medium. Mass-loss rates are thought to be controlled by pulsation-enhanced dust-driven outflows. Here we investigate the relationships between mass loss, pulsations, and radiation, using 3213 luminous Kepler red giants and 135000 ASAS–SN semiregulars and Miras. Mass-loss rates are traced by infrared colours using 2MASS and WISE and by observed-to-model WISE fluxes, and are also estimated using dust mass-loss rates from literature assuming a typical gas-to-dust mass ratio of 400. To specify the pulsations, we extract the period and height of the highest peak in the power spectrum of oscillation. Absolute magnitudes are obtained from the 2MASS Ks band and the Gaia DR2 parallaxes. Our results follow. (i) Substantial mass loss sets in at pulsation periods above ∼60 and ∼100 days, corresponding to Asymptotic-Giant-Branch stars at the base of the period-luminosity sequences C′ and C. (ii) The mass-loss rate starts to rapidly increase in semiregulars for which the luminosity is just above the red-giant-branch tip and gradually plateaus to a level similar to that of Miras. (iii) The mass-loss rates in Miras do not depend on luminosity, consistent with pulsation-enhanced dust-driven winds. (iv) The accumulated mass loss on the Red Giant Branch consistent with asteroseismic predictions reduces the masses of red-clump stars by 6.3%, less than the typical uncertainty on their asteroseismic masses. Thus mass loss is currently not a limitation of stellar age estimates for galactic archaeology studies.

scholarly journals WD 1856 b: a close giant planet around a white dwarf that could have survived a common envelope phase

2020 ◽  
Vol 501 (1) ◽  
pp. 676-682
Author(s):  
F Lagos ◽  
M R Schreiber ◽  
M Zorotovic ◽  
B T Gänsicke ◽  
M P Ronco ◽  
...  
Keyword(s):  
White Dwarf ◽  
Evolutionary History ◽  
Giant Planet ◽  
Asymptotic Giant Branch ◽  
Orbital Energy ◽  
Current Position ◽  
Recombination Energy ◽  
Additional Energy ◽  
Common Envelope ◽  
History Of

ABSTRACT The discovery of a giant planet candidate orbiting the white dwarf WD 1856+534 with an orbital period of 1.4 d poses the questions of how the planet reached its current position. We here reconstruct the evolutionary history of the system assuming common envelope evolution as the main mechanism that brought the planet to its current position. We find that common envelope evolution can explain the present configuration if it was initiated when the host star was on the asymptotic giant branch, the separation of the planet at the onset of mass transfer was in the range 1.69–2.35 au, and if in addition to the orbital energy of the surviving planet either recombination energy stored in the envelope or another source of additional energy contributed to expelling the envelope. We also discuss the evolution of the planet prior to and following common envelope evolution. Finally, we find that if the system formed through common envelope evolution, its total age is in agreement with its membership to the Galactic thin disc. We therefore conclude that common envelope evolution is at least as likely as alternative formation scenarios previously suggested such as planet–planet scattering or Kozai–Lidov oscillations.

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