scholarly journals Radial density profiles of PNe halos from numerical models of mass-loss history

2011 ◽  
Vol 7 (S283) ◽  
pp. 518-519
Author(s):  
Juan-Luis Verbena ◽  
Klaus-Peter Schröder ◽  
Astrid Wachter
Keyword(s):  
Mass Loss ◽  
Observational Data ◽  
Numerical Models ◽  
Stellar Mass ◽  
Line Of Sight ◽  
Red Giants ◽  
Agb Stars ◽  
Radial Density ◽  
Density Profiles ◽  
Outflow Velocity

AbstractWe review the stellar mass loss of red giants and tip-AGB objects analizing the variation in the outflow velocity for different mass models (Wachter et al. 2002). We approach the superwind problem and see the evolution of tip-AGB stars via previously made mass-loss histories that are consistent with the Weidemann initial-final mass relationship (for carbon-rich stars). Finally density profiles are produced from these mass-loss histories, and the corresponding line-of-sight integration is compared with observational data (Phillips et al. 2009). We note the resemblance between the results obtained with our models and the observational data. We are thus able to reproduce the general trends of the emission from simple models (see Verbena et al. 2011).

scholarly journals Mapping dark matter and finding filaments: calibration of lensing analysis techniques on simulated data

2020 ◽  
Vol 496 (3) ◽  
pp. 3973-3990
Author(s):  
Sut-Ieng Tam ◽  
Richard Massey ◽  
Mathilde Jauzac ◽  
Andrew Robertson
Keyword(s):  
Gravitational Lensing ◽  
Simulated Data ◽  
Line Of Sight ◽  
Radial Density ◽  
Density Profiles ◽  
Analysis Techniques ◽  
Scientific Goal ◽  
Mass Mapping ◽  
Mapping Techniques ◽  
Suppress Noise

ABSTRACT We quantify the performance of mass mapping techniques on mock imaging and gravitational lensing data of galaxy clusters. The optimum method depends upon the scientific goal. We assess measurements of clusters’ radial density profiles, departures from sphericity, and their filamentary attachment to the cosmic web. We find that mass maps produced by direct (KS93) inversion of shear measurements are unbiased, and that their noise can be suppressed via filtering with mrlens. Forward-fitting techniques, such as lenstool, suppress noise further, but at a cost of biased ellipticity in the cluster core and overestimation of mass at large radii. Interestingly, current searches for filaments are noise-limited by the intrinsic shapes of weakly lensed galaxies, rather than by the projection of line-of-sight structures. Therefore, space-based or balloon-based imaging surveys that resolve a high density of lensed galaxies could soon detect one or two filaments around most clusters.

Quasi-Periodic Shells Around Post-AGB Stars and PNe

2003 ◽  
Vol 209 ◽  
pp. 123-126
Author(s):  
Yvonne Simis
Keyword(s):  
Mass Loss ◽  
Formation Mechanism ◽  
Stellar Mass ◽  
Agb Stars ◽  
Lower Mass ◽  
Model Calculations

In a previous paper (Simis, Icke, & Dominik 2001, hereafter SID2001), it was shown that the concentric, quasi-periodic shells around IRC +10216 seem to originate on the AGB, as an instability in the wind. In this contribution a grid of model calculations is used to investigate the formation mechanism further. Comparing the calculations leads to the conclusion that mass loss variability on the AGB, and hence the formation of shells, is more likely to occur for relatively high stellar mass and temperature, and low luminosity than for lower mass and temperature and higher luminosity.

scholarly journals Mid-IR Imaging of AGB Stars and Circumstellar Modelling

1995 ◽  
Vol 155 ◽  
pp. 429-430
Author(s):  
M. Busso ◽  
L. Origlia ◽  
G. Silvestro ◽  
M. Marengo ◽  
P. Persi ◽  
...  
Keyword(s):  
Mass Loss ◽  
Stellar Mass ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Direct Imaging ◽  
Intermediate Mass ◽  
Convective Envelope ◽  
Rich Phase ◽  
Ir Imaging ◽  
Optical Wavelengths

The evolution of low and intermediate mass (1-8 M⊙) stars along the Asymptotic Giant Branch (AGB) is ruled by processes of mass loss, causing the whole convective envelope to be gradually ejected into space. If the stellar mass is sufficiently high (M ≥ 1.5 M⊙) the envelope itself becomes enriched in nucleosynthesis products (carbon and s-process nuclei) and the star evolves into a C-rich phase. AGB stars are hence surrounded by O-rich or C-rich envelopes, opaque at optical wavelengths, which are best studied through direct imaging in the infrared (IR).

scholarly journals Mass loss from dusty, low outflow-velocity AGB stars

2007 ◽  
Vol 475 (2) ◽  
pp. 559-568 ◽  
Author(s):  
J. M. Winters ◽  
T. Le Bertre ◽  
J. Pety ◽  
R. Neri
Keyword(s):  
Mass Loss ◽  
Agb Stars ◽  
Outflow Velocity

scholarly journals Mass-loss from dusty, low outflow-velocity AGB stars

2003 ◽  
Vol 409 (2) ◽  
pp. 715-735 ◽  
Author(s):  
J. M. Winters ◽  
T. Le Bertre ◽  
K. S. Jeong ◽  
L.-Å. Nyman ◽  
N. Epchtein
Keyword(s):  
Mass Loss ◽  
Agb Stars ◽  
Outflow Velocity

scholarly journals ISOGAL and 2MASS Study of the Central Regions of Our Galaxy

2001 ◽  
Vol 205 ◽  
pp. 282-283
Author(s):  
D.K. Ojha ◽  
A. Omont ◽  
S. Ganesh ◽  
Isogal Team
Keyword(s):  
Mass Loss ◽  
Interstellar Extinction ◽  
Large Mass ◽  
Red Giants ◽  
Agb Stars ◽  
Galactic Bulge ◽  
Central Regions ◽  
Loss Rates

We report the study of ISOGAL fields in the outer galactic bulge (-1.5° < l < +1.6°, −2.6° < b < + 6.0°, area ∼ 0.42 deg2). We have combined 15 μm and 7 μm ISOCAM observations with 2MASS JHKS data to determine the nature of the sources and the interstellar extinction. Most of the ISOGAL sources show evolution of mass-loss rates in the range 3×10−8 to 1 × 10−6 (M⊙/year). Most of the detected sources are red giants above the RGB tip; a few of them show an excess in J-Ks and Ks-[15] colors. These sources are AGB stars with large mass-loss rates.

scholarly journals The hydrodynamical structure of circumstellar envelopes around low mass-loss rate, low outflow velocity AGB stars

2002 ◽  
Vol 388 (2) ◽  
pp. 609-614 ◽  
Author(s):  
J. M. Winters ◽  
T. Le Bertre ◽  
L.-Å. Nyman ◽  
A. Omont ◽  
K. S. Jeong
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Agb Stars ◽  
Circumstellar Envelopes ◽  
Outflow Velocity ◽  
Low Mass

scholarly journals A study of stellar orbit fractions: simulated IllustrisTNG galaxies compared to CALIFA observations

2019 ◽  
Vol 489 (1) ◽  
pp. 842-854 ◽  
Author(s):  
Dandan Xu ◽  
Ling Zhu ◽  
Robert Grand ◽  
Volker Springel ◽  
Shude Mao ◽  
...  
Keyword(s):  
Observational Data ◽  
Mass Range ◽  
Stellar Mass ◽  
Model Uncertainties ◽  
Massive Galaxies ◽  
Hubble Sequence ◽  
Galaxy Sample ◽  
The Mean ◽  
Stellar Orbit

ABSTRACT Motivated by the recently discovered kinematic ‘Hubble sequence’ shown by the stellar orbit-circularity distribution of 260 CALIFA galaxies, we make use of a comparable galaxy sample at z = 0 with a stellar mass range of $M_{*}/\mathrm{M}_{\odot }\in [10^{9.7},\, 10^{11.4}]$ selected from the IllustrisTNG simulation and study their stellar orbit compositions in relation to a number of other fundamental galaxy properties. We find that the TNG100 simulation broadly reproduces the observed fractions of different orbital components and their stellar mass dependences. In particular, the mean mass dependences of the luminosity fractions for the kinematically warm and hot orbits are well reproduced within model uncertainties of the observed galaxies. The simulation also largely reproduces the observed peak and trough features at $M_{*}\approx 1\rm {-}2\times 10^{10}\, \mathrm{M}_{\odot }$ in the mean distributions of the cold- and hot-orbit fractions, respectively, indicating fewer cooler orbits and more hotter orbits in both more- and less-massive galaxies beyond such a mass range. Several marginal disagreements are seen between the simulation and observations: the average cold-orbit (counter-rotating) fractions of the simulated galaxies below (above) $M_{*}\approx 6\times 10^{10}\, \mathrm{M}_{\odot }$ are systematically higher than the observational data by $\lesssim 10{{\ \rm per\ cent}}$ (absolute orbital fraction); the simulation also seems to produce more scatter for the cold-orbit fraction and less so for the non-cold orbits at any given galaxy mass. Possible causes that stem from the adopted heating mechanisms are discussed.

scholarly journals Discovery of Infrared Stars in Globular Clusters in the Magellanic Clouds and Their Light Variations

1998 ◽  
Vol 11 (1) ◽  
pp. 395-395
Author(s):  
S. Nishida ◽  
T. Tanabé ◽  
S. Matsumoto ◽  
T. Onaka ◽  
Y. Nakada ◽  
...  
Keyword(s):  
Mass Loss ◽  
Globular Clusters ◽  
Main Sequence ◽  
Near Infrared ◽  
Magellanic Clouds ◽  
Infrared Light ◽  
Agb Stars ◽  
Dust Shells ◽  
Infrared Stars ◽  
Infrared Survey

A systematic near-infrared survey was made for globular clusters in the Magellanic Clouds. Two infrared stars were discovered in NGC419 (SMC) and NGC1783 (LMC). NGC419 and NGC1783 are well-studied rich globular clusters whose turn-off masses and ages are estimated MTO ~ 2.0 Mʘ and т ~1.2 Gyr for NGC419, and MT0 ~ 2.0 Mʘ and т ʘ 0.9 Gyr for NGC1783, respectively. The periods of the infrared light variations were determined to be 540 dfor NGC419IR1 and to be 480 d for NGC1783IR1, respectively. Comparison of the measurements with the period—if magnitude relation for carbon Miras in the LMC by Groenewegen and Whitelock(1996) revealed that the Kmagnitudes of the infrared stars were fainter by about 0.3 — 0.8 magnitude than those predicted by the P — K relation. This deviation can be explained if the infrared stars are surrounded by thick dust shells and are obscured even in the K band. The positions of NGC419IR1and NGC1783IR1 on the P — K diagram suggest that AGB stars with the main sequence masses of about 2 Mʘ start their heavy mass-loss when P ʘ 500 d.

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